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UNITED STATES OF AMERICA. 



AN ELEMENTAEY COURSE 



IN 



INORGAMO PHARMACEUTICAL 
AND MEDICAL CHEMISTRY. 



DESIGNED ESPECIALLY FOR STUDENTS 
OF PHARMACY AND MEDICINE. 



y 



FREDERICK J. WULLING, 

Bean, and Professor of the Practice and Theory of Pharmacy, and of Pharmor 

ceutical Chemistry at the College of Pharmacy of the University of 

Minnesota : late Professor of Inorganic Pharmaco- Diagnosis 

at the Brooklyn College of Pharmacy ; formerly Iiistruc- 

tor of Pharmacy at the College of Pharmacy of 

the City of New York : Author of 

" The Evolution of Botany,''' etc. 



Kevised, and reprinted prom the Pharmaceutical Record. 



NOV 2C1BS4 

FIRST EDIT! 






FIRST THOUSAND. "> ^ ' ' ^ """^ 



5 2/;^ 



NEW YORK : 

JOHN WILEY & SONS, 
53 East Tenth Street. 

1894. 



Copyright, 1894, 

BY 

Frederick J. Wulling. 



ROBERT DRUMMOND, ELECTROTYPER AND PRINTER, NEW YORK. 



PEEFACE. 



The Elementary Course in Pharmaceutical and Medical 
Chemistry was first published in the Pharmaceutical 
Record during the year 1892. Its original purpose was to 
direct and guide those pharmaceutical and medical students 
who had not the advantages of the personal direction of 
a teacher in their chemical studies. The course admirably 
carried out this purpose with its early readers, and its pub- 
lication in book-form is in response to requests from many 
of these readers, and from teachers of chemistry. It was 
the author's intention to thoroughly revise the course, to 
eliminate much and to add more; but the many duties in- 
cumbent on a busy life havo not permitted more than a 
partial revision. The method of presentation is the result 
of the author's experience as a teacher of pharmaceutical 
chemistry. The work is presented in such form that no 
part of it is complete without the other; it is necessary to 
study the book from beginning to end to follow its 
logical sequence. Kepetition is adopted purposely; the 
statements which are repeated, perhaps frequently, are 
those which beginners do not always grasp the first time 
they are made. Eepetition in an elementary course such as 
this is essential; it has the advantage which lies in the 
presentation of the same facts in so many different forms 

lit 



IV PREFACE. 

of language that the reader will find at least one form un- 
derstandable. In a few instances where it seemed well, 
the language of others is quoted to make clearer the 
point under discussion. Facts in chemical philosophy are 
scattered through the book and are given where they 
seemed to fit best and where their application is most 
appropriate. The course is graded in a manner which 
requires that it be studied page by page. Its plan is to 
gradually lead up to the comprehension of the chemistry 
of the inorganic salts official in the United States Pharma- 
copoeia. The explicitness and detail of the treatment of 
the subjects up to the metals and their salts render brevity 
thereafter possible, in that the study of the salts requires 
essentially only the application of the principles laid down 
in the first half of the course. Where repetition is useless 
it is not employed ; so it has been possible, to an extent, 
to study the properties of salts of the same metal collect- 
ively. 

The author is gratefully appreciative of the aid rendered 
by those who have favored him with valuable suggestions, 
and to those who have so kindly assisted in reading and 
correcting the proof. 

He desires also to express his gratitude for the favor 
with which the course was received during its first publica- 
tion, and he indulges the hope that in its present form it 
will be still more worthy of the confidence of pharmaceuti- 
cal and medical students and teachers. 

Minnesota State University, 

Minneapolis, Nov. 1894. 



CONTENTS. 



PAGE 

A Course in Elementary Inorganic Pharmaceutical 

AND Medical Chemistry 1 

Introductory 2-20 

Molecular Forces, Atomic Force, The Elements, Non- 
Metals, Metals, Physical Properties of the Elements, Chem- 
ical Properties of the Elements, Atomic Weights, Law of 
Definite Chemical Proportion, Quantivalence Table of 
Elements, Quantivalence, Symbols and Atomic Weights ; 
Chemical Notation. 

NON-METALS. 

Oxygen 21-28 

History, Occurrence in Nature, Preparation, Physical 
Properties, Chemical Properties, Uses and Compounds in 
Pharmacy and Medicine, Ozone, Tests and Experiments. 

Hydrogen 28-34 

History, Occurrence in Nature, Source, Preparation, Phys- 
ical Properties, Chemical Properties, Tests and Experi- 
ments, Uses in Pharmacy, Compounds. 

Watsr 34-48 

Composition, General Properties, Chemical Properties, 
Natural Waters, Atmospheric, Terrestrial, Hard Waters, 
Mineral Waters, Well-Waters, Purification of Water, Per- 
oxide of Hydrogen. 

Nitrogen 48-51 

History, Occurrence in Nature, Functions in Nature, 
Properties, Preparation, Compounds, Tests for Nitrates. 

V 



VI CON"TENTS. 

PAGE 

Oxygen and Nitrogen as the Atmosphere 51-56 

Chemical Constituents of the Air. 

Carbon 56-66 

Occurrence in Nature, Properties, Compounds of Carbon 
with Hydrogen, Illuminating Gas, Compounds of Carbon 
with Hydrogen and Oxygen, Alkaloids and Glucosides, 
Compounds with Oxygen, Carbon with the Halogens, Car- 
bon with Nitrogen, Carbon with Sulphur. 

The Halogens. 

cht.orine 66-80 

History, Occurrence in Nature, Preparation, Properties, 
Compounds Containing Chlorine, A Lesson in Nomenclat- 
ure, Experiments, Diffusion of Gases, Bleaching Properties, 
Disinfecting and DeodorizingProperties, Affinity of Chlorine 
for Hydrogen, Affinity of Chlorine for Bases, Solvent Power 
of Chlorine, Tests of Identity of Chlorine as Chloride, Chlo- 
rine in Pharmacy, Calx Chlorata, Liquor Sodae Chloratse. 

Iodine 80-85 

Occurrence in Nature, Source, Preparation, Purification, 
Detection of Impurities, Properties, Compounds, Pharma- 
ceutical Preparations, Tests for Iodine and Iodides, 

Bromine 85-86 

Occurrence in Nature, Preparation, Properties, Com- 
pounds, Tests. 

Fluorine 86 

Sulphur 87-96 

Occurrence in Nature, Preparation, Properties, Official 
Sulphurs, The Writing of Salts. 

Phosphorus 96-107 

Occurrence in Nature, Source, Preparation, Properties, 
Experiments, Uses, Phosphorus in Pharmacy and Medicine. 

Boron 107-114 

Occurrence in Nature, Preparation, Boric Acid, Tests for 
Purity of Boric Acid, Uses of Boric Acid, Borax. 



CONTENTS. Vll 



INORGANIC ACIDS. 

PAGE 

The Study of Acids and Salts, Antidotes to Mineral Acids, 

Medical Properties of the Acids 115-125 

Sulphuric Acid 125-133 

Preparation, Tests for Impurities, Uses, Dilute Sulphuric 
Acid, Aromatic Sulphuric Acid, Solid Sulphuric Acid. 

Sulphurous Acid 132-133 

Preparation, Properties. 

Nitric Acid 134-139 

Preparation (Functions and Uses of Equations), Prop- 
erties, Impurities, Uses in Pharmacy and Medicine, Dilute 
Nitric Acid. 

Hydrochloric Acid, 139-144 

Preparation, Uses, Antidote, Dilute Hydrochloric Acid. 

NiTROHYDROCHLORIC ACID 144-145 

Dilute Nitrohydrochloric Acid. 
Dilute Hydrobromic Acid 145-147 

Preparation, Tests, Impurities, Uses. 
Hydriodic Acid 148-149 

Preparation, Properties, Uses. 
Phosphoric Acid 149-156 

Preparation, Varieties, Properties, Impurities, Tests, 
Dilute Phosphoric Acid, Glacial Phosphoric Acid, Phos- 
phorous Acid. 
Arsenous Acid 156-158 

Preparation, Poisonous Properties, Antidote, Uses. 
Chromic Acid 158-159 

Properties, Uses. 

THE METALS. 

Physical Properties, Chemical Properties, Unions with the 
Halogens, Haloid Salts, Normal, Acid, and Double Salts, 

Basic Salts or Oxy-salts, Kinds of Formula 159-172 

The Alkalies. 

Properties, Alums 172-177 



Vlll CONTENTS. 

PAGE 

Potassium Salts and Preparations 177-190 

Sources, Tests, Impurities, Carbonate, Bicarbonate, Sul- 
phite, Acetate, Citrate, Solution of the Citrate, Mixture of 
the Citrate, Effervescent Citrate, Solution of the Arsenite, 
Sulphurated Potassa, Hypophosphite, Potassa, Potassa by- 
Alcohol, Potassa with Lime, Solution of Potassa, Perman- 
ganate, Iodide, Bromide, Ferrocyanide, Cyanide, Bichro- 
mate, Chlorate, Troches of the Chlorate, Bitartrate, Tartrate, 
Potassium and Sodium Tartrate, Nitrate, Sulphate. 

Sodium Salts and Preparations 190-irS 

Sources, Carbonate, Dried Carbonate, Bicarbonate, Com- 
mercial Bicarbonate, Soda, Solution of Soda, Arsenate, Bi- 
sulphite, Sulphite, Bromide, Chloride, Hypophosphite, 
Iodide, Phosphate, Pyrophosphate, Acetate, Benzoate, 
Salicylate, Sulphocarbolate, Borate, Nitrate, Sulphate, 
■ Chlorate, Hyposulphite, Solution of Chlorinated Soda, 
Solution of the Arsenate, Solution of the Silicate, Troches 
of the Bicarbonate, Rhubarb and Soda Mixture. 

Ammonium Salts and Preparation 199-205 

Tests, Sources, Chloride, Ammonia-Water, Stronger 
Ammonia- Water, Ammonia Liniment, Ammonia Spirit, 
Aromatic Spirit, Carbonate, Solution of the Acetate, 
Benzoate, Bromide, Nitrate, Valerianate, Iodide. 

Lithium Salts 205-207 

Carbonate, Benzoate, Bromide, Citrate, Salicylate. 
Metals of the Alkaline Earths. 

Calcium Salts and Preparations 207-213 

Sources, Prepared Chalk, Precipitated Carbonate, Troches 
of Chalk, Chloride, Bromide, Lime, Lime Water, Syrup of 
Lime, Lime Liniment, Sulphurated Lime, Chlorinated Lime, 
Labarraque's Solution, Hypophosphite, Precipitated Phos- 
phate. 

Strontium Salts 213-216 

Properties, Tests for Identity and Purity, Bromide, Iodide, 
Lactate. 
Barium 216 



CONTENTS. IX 

Magnesium Group. 

PAGE 

Magnesium Salts and Preparations 216-320 

Tests, Sulphate, Carbonate, Magnesia, Heavy Magnesia, 
Solution of the Citrate, Effervescent Citrate, Sulphite. 

Zinc Salts and Preparations 220-224 

Analytical Keactions, Sulphate, Impurities, Bromide, 
Valerianate, Precipitated Carbonate, Oxide, Ointment of 
the Oxide, Acetate, Solution of the Chloride, Chloride, 
Phosphide. 

Aluminum Salts 224-226 

Analytical Keactions, Alum, Dried Alum, Hydrate, Sul- 
phate. 

Cerium 226 

Oxalate. 

Lead Salts and Preparations , 226-232 

Analytical Reactions, Oxide, Acetate, Solution of Subace- 
tate. Liniment of the Subacetate, Cerate of the Subacetate, 
Lead-Plaster, Diachylon Ointment, Nitrate, Iodide, Oint- 
ment of the Iodide, Carbonate, Ointment of the Carbonate. 

Copper Group. 

Copper Salts „ . .232-233 

Analytical Reactions, Sulphate, Acetate. 

Mercury and Its Salts and Preparations 233-244 

Important Reactions, Mass of Mercury, Mercurial Oint- 
ment, Mercurial Plaster, Ammoniac Plaster with Mercury, 
Mercury with Chalk, Mercuric Chloride, Mercurous Chloride, 
Ammoniated Mercury, Red Iodide, Yellow Iodide, Yellow 
Oxide, Ointment of Yellow Oxide, Oxalate, Red Oxide, Oint- 
ment Red Oxide, Cyanide, Ointment Ammoniated Mercury, 
Yellow Sulphate, Red Sulphide, Solution of Nitrate, Citrine 
Ointment. 

Silver Salts 244-247 

Analytical Reactions, Nitrate, Fused Nitrate, Diluted 
Nitrate, Cyanide, Oxide, Iodide. 

Iron Group. 
Iron Salts and Preparations 247-269 



X CONTENTS. 

PAGE 

Sources, Saccharated Iodide, Syrup of Ferrous Iodide, 
Ferrous Lactate, Ferric Chloride, Solution Ferric Chloride, 
Tincture Ferric Chloride, Solution Iron and Ammonium 
Acetate, Ferrous Sulphate, Granulated Ferrous Sulphate, 
Dried Ferrous Sulphate, Pills Aloes and Iron, Saccharated 
Ferrous Carbonate, Mass of Ferrous Carbonate, Reduced 
Iron, Pills of Ferrous Iodide, Compound Iron Mixture, Pills 
of Carbonate, Ferric Hypophosphite, Solution of Ferric 
Subsulphate, Solution of Ferric Sulphate, Ferric Ammonium 
Sulphate, Ferric Valerianate, Ferric Hydrate with Magnesia, 
Ferric Hydrate, Troches of Iron, Iron-Plaster, Solution of 
Ferric Acetate, Tincture of Ferric Acetate, Solution of 
Ferric Nitrate, Scale Salts, Soluble Ferric Phosphate, Syrup 
of the Phosphates of Iron, Quinine and Strychnine ; Soluble 
Ferric Pyrophosphate, Ferric Citrate, Iron and Ammonium 
Citrate, Wine of Ferric Citrate, Iron and Strychnine Citrate, 
Soluble Iron and Quinine Citrate. 
Manganese Salts 269-270 

Dioxide, Sulphate. 

Metalloides. 
Aksenic Salts and Peepabations 270-278 

Occurrence, Preparation, Properties, Physical and Chemi- 
cal; Analytical Reactions, Solution Arsenous Acid, Solution 
Potassium Arsenite, Iodide, Solution of Arsenic and Mer- 
curic Iodide, Sodium Arsenate, Solution of Sodium Arsenate, 
Paris Green. 
Antimony Salts and Prepabations 278-28H 

Occurrence, Preparation, Properties, Reactions, Sulphide, 
Purified Sulphide, Sulphurated Antimony, Compound 
Pills of Antimony, Oxide, Antimonial Powder, Antimony 
and Potassium Tartrate, Wine of Antimony. 
Bismuth Salts 283-286 

Occurrence, Reactions, Subnitrate, Subcarbonate, Citrate, 
Bismuth and Ammonium Citrate. 



A Course in Elementary Inorganic 
Pharmaceutical and Medical Chemistry. 



INTEODUOTORY. 



Studeii^'ts in any branch of chemistry must all begin at 
the same starting-point. They must necessarily first ac- 
quire the knowledge of the fundaments, the elements of 
the science^ upon which, when once their own, they can 
construct or build any division of the science. So the 
student in pharmaceutical chemistry must first acquaint 
himself with the principles of chemistry without reference 
to the application of chemistry to pharmacy. When he 
has accomplished that, the principles may then be applied 
to pharmacy. 

Molecular Forces. — In order to intelligently understand 
the subject it will be necessary to deviate a little and enter 
the field of physics, to get enough knowledge from that to 
better comprehend the meaning of chemistry. 

The universe, the sum of all created things, is made up 
of what is termed matter, which material assumes three 
different forms, the solid, liquid, and gaseous. All things 
are in one of these three conditions, and the condition in 
which any given portion of matter exists is dependent 
upon the predominance of one or more of the natural 
forces. A given mass of matter is made up of little parti- 
cles which are held together by the force called cohesion — 
that is, the particles of matter through the agency of thia 



2 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

force of attraction are made to unite to form a mass. If 
this force of cohesion is very strong, we have bodies which 
are very hard; is this force less strong, the bodies are soft 
or liquid. When this attractive force is altogether absent, 
and is replaced by another force having just the contrary- 
tendencies — that is, to repel the particles from each other 
— we have gases as a result. This latter force is called 
repulsion. 

It must be remembered that these forces act only on 
and between the small particles mentioned, which we will 
henceforth call molecules. A molecule is therefore the 
smallest particle of any kind of matter which will retain 
the characteristics or nature of the mass or body of which 
it is a part, and on and between which particles the forces 
of attraction and repulsion act. The latter two forces are 
often spoken of as molecular forces, because they concern 
themselves exclusively with molecules. The science which 
concerns itself with the molecular forces is termed physics 
or natural philosophy. Physics in a limited sense studies 
the nature of, and the phenomena observed in, bodies in 
which there is no change in composition or construction. 
Chemistry, on the other hand, comprehends only the 
internal structure, as it were, of the molecules. When 
we subdivide a given mass or body physically until it 
becomes impossible to further subdivide it without affect- 
ing its construction or internal structure, we arrive at what 
we call a molecule, and at this point we have reached the 
limit of physics, the sharp line which separates physics 
from chemistry. It is not impossible to further subdivide 
the molecule, but when we do so we destroy its internal 
structure and enter thereby the realm of chemistry. The 
molecule may be decomposed, resolved, into still smaller 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 6 

particles, to which we apply the term " atoms.'' Atoms, 
therefore, make molecules, and molecules mass, "We have 
learned that the molecules in forming mass by aggregating 
are held together by the force of attraction, and that this 
force is restricted to molecules. Now, the force which 
unites atoms to form molecules is a very different one from 
the molecular, and is only exerted among or between atoms. 
The Atomic Force. — When a molecule has been resolved 
into its constituent atoms the process of subdivision has 
been carried to its utmost extent. The resolution of mole- 
cules into atoms usually gives us several kinds of atoms, 
and, because the atoms represent the ultimate division of 
matter, when we have different kinds of atoms we must 
have different kinds of matter. Chemists have found that 
there are between 65 and 70 different kinds of atoms, and 
consequently there must be as many different ultimate 
kinds of matter. Such an ultimate kind of matter, which, 
when its molecule is resolved into atoms, yields only one 
kind of atoms, is termed an elemsnt, or a simple substance. 
These 65 or 70 simple substances unite with each other in 
various proportions, and form the innumerable diversity of 
substances and bodies in the universe. This union is in 
obedience to the chemical or atomic force, or chemical 
affinity, or chemism, and takes place only between atoms. 
Apparently molecules unite with each other chemically at 
times; the union is, however, between the atoms constitut- 
ing the molecules. There is as sharp a distinction between 
the molecular and atomic forces as there is between a mole- 
cule and an atom. When molecules unite to form a mass 
the latter has all the properties which the molecules had, 
or vice versa, but whcD atoms unite, the resulting molecules 
have no properties in common with the atoms which 



4 PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 

formed them. In other words, when atoms unite with one 
another they lose their identity, their individuality, and 
the resulting molecules are totally different in all respects. 
For instance, if we unite a molecule of iron with another 
molecule of iron, we get a mass of iron, which still retains 
all the properties of the iron; but if we unite an atom of 
iron with an atom of iodine, we get a molecule of iodide of 
iron, which is totally different from either the iron or the 
iodine. In the latter union the chemical force exerts itself, 
in the former the molecular. 

The student will thus far remember: 

That atoms are the smallest particles of matter which 
will enter into chemical union, and 

That this chemical union destroys the identity of the 
kind of matter acted upon, forming bodies altogether dif- 
ferent from those entering into their composition. 

That the chemical force is that force which induces and 
governs that kind of union. 

That molecules are the smallest particles of matter which 
can retain the properties of the mass of which they are a 
part, and 

That they are held together by the molecular force. 

Physics relates to the study of bodies in which there is 
no change in composition. 

Chemistry studies the phenomena observed in bodies in 
which there is a change in structure, and the law inducing 
the change. 

The Elements. 

The 65 or 70 simple bodies or elements in an innumer- 
able variety of combinations — chemical combinations — 
make up the sum of matter of the earth and all upon it. 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 5 

In thus uniting to form this diversity of bodies, the ele- 
m^its behave principally in one of two ways (these ways 
will be alluded to later, when the student will have be- 
come better j&tted to understand them), which ways afford 
us a convenient means for subdivision into two primary 
groups — the metals and non-metals. Each of these is for 
convenience further subdivided into smaller groups, the 
elements of each group having some property or properties 
in common, which makes their classification desirable. 

The names of the elements are derived from the Greek 
and Latin, and usually indicate something of the nature 
of the element. For convenience and brevity symbols are 
employed in place of the whole names, these symbols being 
shorthand for the longer Greek or Latin names. Of the 
whole number of elements a few more than half are im- 
portant enough to merit mention here, the remainder 
being of rare occurrence. The following represents a 
convenient classification of the elements into groups and 
sub-groups : 

NOK-METALS. 

Names. Symbols. 

Oxygen ] 

Sulphur S r^ 

Selenium Se ^ Oxygen group. 

Tellurium Te J 

Chlorine. Cn 

Bromine Br tt i 

Iodine I ^ Halogen group. 

Fluorine Fl J 

Phosphorus , P '] 

Carbon , C I 

Silicon Si \- 

Boron ; .Bo | 

Nitrogen N J 

Arsenic , As 

Antimony (Stibium) Sb )- Metalloids. 

Bismuth Bi 



6 PHARMACEUTICAL AKt) MEDICAL CHEMISTRY. 



Metals. 

Names. Symbols. 

Potassium (Kalium) K "] 

Sodium (Natrium) Na .,, ,. 

Lithium. : Li (^ Alkalies. 

Ammonium (NH4) 

Calcium Ca 

Barium Ba ^ Alkaline earths. 

Strontium Sr 



I 



Magnesium Mg 

Zinc Zn ^ Magnesium group. 

Cadmium Cd 

Silver (Argentum) Ag 

Mercury (Hydrargyrum) Hg \ Copper group. 

Copper (Cuprum) Cu 

Iron (Ferrum) Fe ") 

Sr!r-:;;:::;:;;;.::::::::;.v;;.v;;:^o [ '- ^-p- 

Nickel Ni J 

Chromium Cr ) r^\ 

Molybdenum Mo j- Chromium group. 

ffsmX".^'!'':r^.;;;;:;::::;:;::;;;;;;.l'^ 

elJd (Sumj: : : ::::::::::::::::::■.:::::: II \ p>-«-- g^-p^ 

Aluminum Al 

Lead (Plumbum) Pb 

Tin (Stannum) ... Sn 

Hydrogen H 

The above, it must be remembered, are not all the ele- 
ments known, nor are those mentioned in any one group 
all that may belong to that group; they are the more im- 
portant ones. It will be seen that antimony and bismuth 
are found in both primary divisions — these and the metal- 
loids will be considered further on. 

The student at this point need only remember the 
names and symbols of the elements and the two primary 
divisions. 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 7 

Physical Properties of the Elements. 

The elements, as elements, exist in three forms; some 
are solid, some liquid and some gaseous. Mercury and 
bromine are liquid. Hydrogen, oxygen, chlorine, nitrogen 
and fluorine are gases, all the rest solids. The condition 
in which an element, or for that matter any compound, ex- 
ists, is dependent upon the prevailing temperature. Many 
solids can be made to become liquid by the application of 
heat, and liquids to become gaseous. By the withdrawal of 
heat gases can be liquefied and liquids solidified. Oxygen 
can be liquefied by pressure and cold. Mercury will be- 
come solid, just as water will, if the temperature is low 
enough. On the other hand, mercury and water and 
other elements or compounds can be changed into gases 
by heat, in which condition they will remain as long as 
the temperature is not lowered. 

Most of the elements are insoluble, odorless and taste- 
less. Sodium and potassium are soluble in water, uniting 
chemically with the water. Chlorine and bromine have 
very characteristic odors. 

Nearly all have considerable chemical affinity, for which 
reason so few are found in nature in the elementary con- 
dition. A few exceptions are nitrogen, gold and copper. 
Sometimes an element occurs in more than one form, as 
carbon, with which we are familiar in the form of the 
diamond, graphite and charcoal; and oxygen, which some- 
times assumes a nature which makes ozone of it. These 
COiiditions are termed allotropic, and are probably due to 
the different arrangement of atoms in the molecules. Two 
atoms of oxygen make a molecule of oxygen, but if the 
molecule contains three atoms of oxygen we call it ozone. 



8 PHABMACEUTICAL AKD MEDICAL CHEMISTKY. 

In this case the molecules contain different numbers of 
atoms, but when the number of atoms in the molecule is 
the same, the difference is in the arrangement of the 
atoms in the molecule. While some elements are crystal- 
lized — that is, assuming a definite geometrical outline — 
others are amorphous, just the contrary — that is, without 
any regular shape. 

The metallic elements usually have a lustre, a color 
from the white silver to the bluish-gray lead, excepting 
copper, which is red, and gold, yellow. They differ con- 
siderably in their relative weights, hydrogen being the 
lightest and platinum the heaviest. The metals are, as a 
rule, heavy — platinum being 21^ times as heavy as water. 
Lithium, sodium, and potassium are lighter than water. 

Chemical Properties of the Elements. 

Atomic Weights and the Lav^^ of Defi]!^ite Chemi- 
cal Peoportioi^. — In studying the chemical behavior of 
the elements we enter upon the field of chemistry proper, 
and concern ourselves almost wholly with the atomic force, 
the force binding together the atoms to form compounds. 

The atomic force, or chemical affinity, as it is frequently 
called, exerts itself at the point of contact of two or more 
atoms — that is, if the elements are capable of forming a 
compound; for it must be understood that chemical affinity 
does not exert itself upon or between any two or more 
atoms. This chemical union does not take place in a hap- 
hazard way; on the contrary, certain definite laws govern 
it. If we were to unite hydrogen and oxygen, we would 
find that the union takes place between definite quanti- 
ties of the elements, and that if either were in excess of 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 9 

its definite quantity, so much of either would remain over 
as either was in excess of its definite quantity. For 
illustration, let us observe closely the proportions in which 
hydrogen and oxygen will unite. Both are gases, but we 
may nevertheless weigh them, and in so doing, which is 
necessary, we find that hydrogen weighs less than oxygen 
does, bulk for bulk. If we are careful to take an equal 
volume of each gas, the hydrogen will be found to weigh 
just one-sixteenth as much as the oxygen does; or, on the 
other hand, that oxygen is 16 times heavier than hydro- 
gen. Let the student bear this in mind for the present. 
The weights of equal volumes of the two gases may have 
been found to have been of hydrogen 10, and of oxygen 
160 grains. If these two equal volumes were made to 
unite chemically (by touching the mixture with a lighted 
match), it would be found that all of the hydrogen, but 
only half the oxygen, entered into chemical union; in other 
words, that the 10 grains of the hydrogen united with 80 
grains of the oxygen, and that the other 80 grains of 
oxygen remained unaffected. This experiment might be 
repeated with any desired quantity of the two gases, but 
always with the result that they would unite in the pro- 
portion of 1 of hydrogen and 8 of oxygen ly weight, or 
2 of hydrogen and 1 of oxygen by volume, and that if 
either be in excess of these proportions, that excess will 
not be affected, but will remain unchanged. The product 
of this combination is water. In like manner we could 
induce chemical union between hydrogen and chlorine, 
and the definite chemical proportions would be 1 and 35-1^, 
respectively, by weight, or 1 and 1 hy volume. This product 
would be hydrochloric acid. 

In the case of hydrogen and sulphur in the gaseous con- 



10 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

dition, the proportions hy weight would be, of hydrogen 1 
and sulphur 16, or hy volume, 2 of hydrogen and 1 of 
sulphur. 

Chemists have assumed that all elements in the gaseous 
condition contain in equal volumes, under like conditions, 
an equal number of molecules, and that molecules of ele- 
ments usually consist of two atoms, and that, therefore, 
equal volumes of most elements in the gaseous condition 
contain an equal number of atoms. The weights of atoms 
must, according to this, differ to the extent that equal 
volumes of gases differ in weight. Hydrogen is the light- 
est gas, and if equal volumes of oxygen, chlorine and sul- 
phur are, respectively, 16, 35.5 and 32 times heavier than 
hydrogen, and if we give the hydrogen atom the value of 
1, it is obvious that the weights of the atoms of oxygen, 
chlorine and sulphur must necessarily be 16, 35.5 and 32. 
These figures, therefore, represent the atomic weights of 
these elements. It must be understood that these weights 
are relative. These figures denote not only the atomic 
weights of the elements, but they denote also the propor- 
tions in which they will unite with one or more hydrogen 
atoms. Oxygen will unite in the proportion of 16 with 2 
of hydrogen, chlorine of 35.5 with 1 of hydrogen, and sul- 
phur of 32 with 2 of hydrogen, for the reasons stated and 
others that will be stated further on. 

In this wise the atomic weights of all elements have 
been obtained, in comparing their weights to that of 
hydrogen, either directly or indirectly. Another method 
will be spoken of a little further on. 

Law of Multiple Proportioks.— The student must 
bear in mind also that the proportions in which elements 
unite with hydrogen are the proportions in which they will 



PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 11 

unite with one another. Oxygen will therefore unite with 
sulphur in the proportion of 16 to 32. The atomic weight 
of carbon is found to be 12, of phosphorus 31, of nitrogen 
14. Carbon, phosphorus or nitrogen would therefore unite 
with 16 parts of oxygen in the proportions expressed by 
the numbers expressing their atomic weights. We find, 
though, that these proportions — i.e., those expressed by 
the atomic weights — are not the only ones in which these 
elements will unite. If, in the case of carbon and oxygen, 
32 of oxygen, twice 16, were taken, chemical combination 
would ensue, with the formation of a definite compound. 
Nitrogen and oxygen will unite not only in the proportion 
of 14 and 16, but in such a way that multiple proportions 
of the oxygen with a constant proportion of nitrogen will 
form definite compounds. The known combinations of 
nitrogen and oxygen may serve to illustrate : 



Nitrogen monoxide. 
Nitrogen dioxide. . . 
Nitrogen trioxide. . . 
Nitrogen tetroxide . . 
Nitrogen pentoxide. 



By weight. 

j Nitrogen 28 parts. 

( Oxygen 16 parts. 

( Nitrogen 28 parts. 

( Oxygen 32 parts. 

j Nitrogen 28 parts. 

(Oxygen 48 parts. 

j Nitrogen 28 parts. 

(Oxygen 64 parts. 

j Nitrogen 28 parts. 

( Oxygen. 80 parts. 



The prefixes mono, di, tri, tetra, and penta (oxide) here 
mean, respectively, one, two, three, four and five times one 
oxygen. It will be seen that the proportion of nitrogen 
(28, twice 14) is constant, while the quantity of oxygen 
increases by 16 in the ratio of one, two, three, four and 
five times 16. 



12 PHAKMACEUTICAL Ai^D MEDICAL CHEMISTRY. 

Carbon and oxygen unite in these proportions: 

Carbon 12, and oxygen 16, form carbon monoxide. 

Carbon 12, and oxygen 32, form carbon dioxide. 

This evidences the important law that some elements 
unite in more than one pro'portion, and that the resulting 
definite compoio7ids contain, to a constant proportion of 
one of the elements, multiple ^proportions of the other. 

Carbon monoxide always contains certain fixed and defi- 
nite proportions of carbon and oxygen; it cannot be car- 
bon monoxide if it does not. This is true also of the 
carbon dioxide. All definite compounds consist of the 
same elements in the same proportions, according to our 
first law, and according to the second law, if two elements 
unite in more than one proportion, they unite in multi- 
ples of that proportion, and never in intermediate propor- 
tions. 

Quantivalence. 

We have learned that hydrogen was taken as a standard 
in comparing the weights of atoms of the elements. This 
is not its only function as a standard ; it is also employed 
in establishing the quantivalence or value of atoms in 
replacing other atoms in combination. All atoms have 
value, and these values are constant in most atoms. We 
assume that all atoms have bonds with which they unite 
with each other, and that the number of bonds fixes the 
value of the atom in combining power. So hydrogen and 
chlorine unite atom for atom. So do hydrogen and iodine. 
These atoms have equal values. Hydrogen and oxygen 
unite in the proportion of two atoms of the former to one of 
the latter; three of hydrogen combine with one of arsenic; 
four of hydrogen combine with one of carbon. The oxy- 



PHAEMACEUTICAL Al^B MEDICAL CHEMISTRY. 13 

gen atom has twice the value of hydrogen, arsenic thrice, 
and carbon four times the value. 

Oxygen, having twice the value of hydrogen or of any 
element uniting with hydrogen atom for atom, is said to 
have two bonds, each one of which combines with the one 
bond which each hydrogen atom has. Arsenic, because it 
requires three of hydrogen for combination, is said to have 
three bonds, and carbon, for similar reason, to have four 
bonds. The number of hydrogen atoms the atom of 
another element requires for combination (in case of pos- 
sibility of combination) determines the number of bonds 
that atom has : 

Hydrochloric Arseniuretted Methane or 

acid. Water. hydrogen. marsh gas. 

H H 

H— 01 H— 0— H H— As— H H— C— H 

i 

The value of an atom is not ascertained alone by study- 
ing the number of hydrogen atoms it requires for com- 
bination, but also by observing the number of other atoms 
it can replace in combination. In the above H — — H 
one of the hydrogen atoms can be re2olaced by one atom of 
potassium or one of sodium, hence the sodium and potas- 
sium atoms have the same value which the hydrogen atom 
has. If the oxygen were replaced by sulphur, H — S — H, 
the sulphur would have two bonds, because it replaced the 
oxygen, which needed two atoms of hydrogen for combina- 
tion. The two hydrogen atoms might be replaced by one 
of calcium, Oa=0, therefore calcium would have two 
bonds. Any atom that could replace the calcium would 



14 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

be twice the value of the hydrogen atom in combining 
power, for the same reason. The value of atoms might be 
better understood by assuming that the hydrogen atom is 
a quarter of a dollar, the standard, oxygen half a dollar 
piece, and carbon a dollar. To equal the dollar (carbon) 
with quarters (hydrogen), four of the latter would be re- 
quired; to equal the half dollar (oxygen) with quarters 
(hydrogen), two of the latter would be needed, and to equal 
the dollar (carbon) with half dollars (oxygen), two would be 
required. 

Special terms are used to designate the value of atoms. 
Those having the value of hydrogen are termed monads, 
or they are said to be monatomic {mono, one), or uni- 
valent (unus, one); those combining with or replacing 
two of hydrogen, diads (di, two) or diatomic, or bivalent 
{his, two); those having thrice the value of the hydro- 
gen atom are termed triads {tres, three), triatomic or 
trivalent; the next in order are quadrads or tetrads 
{quadra, four), quadrivalent', pentads {penta, five), or 
pentatomic; hexads (six); septads (seven), etc. 

Atomicity and equivalency are terms synonymous with 
quantivalence and valence, but the term quantivalence is 
to be preferred. 

The subjoined table gives the names of the elements, 
their symbols, quantivalence and atomic weights. The 
student will notice that many of the elements are classed 
in more than one column. Those elements have more 
than one value — they have as many as the table gives 
them. When an atom has more than one value, the values 
will always be expressed by even numbers or by uneven 
numbers, never by both. Thus nitrogen is triad, pentad 
and sometimes septod, but it never has two, four or six 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 



15 



bdnds. In cases where the atomic weight is expressed by 
fractions, the student may remember the nearest whole 
number. 



Elements — ftuantivalence, Symbols, Atomic Weights. 



Monads. 


Diads. 


Triads. 


Tetrads. 


a 

A 

N 


1 

0) 


1 

A 


Hydrogen, 


Oxygen, 0, 16 


Nitrogen, 


Carbon, 


S 


c\ 


H. 1 


Sulphur, S, 32 


N, 14.01 


C, 12 


P 


Fe 


Br 


Chlorine, 


Calcium, 


Phosphorus, 


Silicon, 


CI 


Al 


I 


CI. 35.37 


Ca, 39.91 


P, 30.96 


Si, 28.3 


Br 


Cr 




Bromine, 


Magnesium, 


Gold. 


Platinum, 


I 


Co 




Br, 79.76 


Mg, 24.3 


Au, 196.7 


Pt, 194.3 


As 


Ni 




Iodine, 


Copper, 


Arsenic, 


Fe 


Sb 


Mn 




I, 126.53 


Cu, 63.18 


As, 74.9 


Al 


Bi 






Fluorine, 


Zinc, Zn, 65.1 


Antimony, 


Mn 








Fl, 19 


Strontium, 


Sb, 119.6 


Cr 








Sodium, 


Sr, 87.3 


Bismuth, 


Co 








Na, 23 


Cadmium, 


Bi, 208.9 


Ni 








Potassium, 


Cd, 111.5 


CI 


Ca 








K, 39.03 


Mercury, 


Br 


Ba 








Rubidium, 


Hg, 199.8 


I 


S 








Rb, 85.20 


Tin, Sn, 118.8 




Pb 








Silver, 


Barium, 












Ag, 107.66 


Ba, 136.9 












Caesium, 


Lead, 












Cs, 132.7 


Pb, 206.4 
Iron, Fe, 55.88 
Aluminum, 

Al, 27.04 
Manganese, 

Mn, 54.08 
Chromium, 

Cr, 52 
Cobalt, Co, 58.6 
Nickel, 

Ni,58.6 













16 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Chemical Notation. 

Chemical notation is the recording, by means of symbols, 
the chemical changes, or the migrations of atoms or mole- 
cules in either the formation or the resolution of com- 
pounds; in short, it is the symbolizing of chemical facts. 
We have already employed the first capital letter of the 
Latin or Greek names of the elements as shorthand for the 
whole name. Thus, for hydrogen or oxygen, we simply 
write H and 0. This is not the only function of the sym- 
bol (to represent the name of the element); it means, 
furthermore, one atom of the element, and third, one volume 
of the element in the gaseous condition. A fourth office 
is to represent a constant comhining weight — i.e., the 
atomic weight of the element for which it stands. 

Figures are used to modify some of these functions. 
Large figures placed before a symbol multiply the atoms, 
and therefore also the atomic weights and the volumes in 
gaseous condition. Thus, 2H means two atoms of hydro- 
gen, two volumes, and twice the atomic weight also. A 
small figure written to the right of the symbol, below, has 
the same significance; thus H^ is the same as 2H. A figure 
preceding multiplies all the symbols that follow, as 3HC1 
means three of hydrogen and three of chlorine, but a small 
figure at the lower right of a symbol multiplies only the 
symbol to which it is attached. It would really be incor- 
rect to write 2H, as we would thereby mean two atoms of 
hydrogen uncombined, which cannot thus exist; atoms, 
even of one kind, will combine to form molecules, two 
atoms usually forming one molecule, which molecule in the 
case of hydrogen or oxygen would be expressed : H^ or O^. 
The third function of a symbol, that of representing one 



PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 17 

volume of the element in the state of gas, will perhaps not 
be so easily understood by the student. By referring to 
the fourth function, representing the atomic weight, he 
may the better understand it. In learning the atomic 
weights, the student was informed that they were obtained 
by weighing equal volumes of the elements under like con- 
ditions of pressure, etc., after they had been caused to enter 
the gaseous condition, and that the number expressing the 
number of times the volume of any one gas was heavier than 
an equal volume of hydrogen, the standard, expressed the 
atomic weight of that element, for equal volumes of gases 
in the case of elementary bodies contain equal numbers of 
molecules; and because these, the molecules, contain two 
atoms the volumes must contain equal numbers of atoms. 
The extension or bulk of the volume is arbitrary, so long 
as it be equal to that with which it is compared. 

The position of symbols, too, has some significance. 
HjjO means not only two atoms of hydrogen and one of 
oxygen, etc., but also that the H and are united by 
chemical force and in the proportion expressed by the fig- 
ures 2 and 1, respectively. (1 is always understood, and 
therefore never written.) Written 211^ -(- 0,, it would in- 
dicate a mere mechanical mixture of two molecules of 
hydrogen and one molecule of oxygen, but placed closely 
together it is understood that they represent the compound 
resulting when hydrogen and oxygen unite chemically. 

An atom is represented by a single symbol, but a 'mole- 
cule, which consists of not less than two atoms, is repre- 
sented by as many symbols as it has kinds of atoms in its 
composition, and the collection of symbols representing 
the composition of a molecule is called its formula. The 
formula for a molecule of an element has only a single 



18 PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 

symbol, representing the kind of atoms, together with the 
small figure at the lower right side denoting the number 
of atoms; thus, H^, 0^, Cl^ denote molecules of hydrogen, 
oxygen and chlorine, respectively. The molecules of some 
elements have more than two atoms; phosphorus, P, is 
believed to have four. 

The formula for the molecule of a compound must have 
not less than two kinds of atoms. Calcium carbonate, 
common chalk, contains calcium, carbon and oxygen, and 
its formula is CaCOg — that is, one atom of calcium, one of 
carbon, and three of oxygen — and these elements are united 
in the proportions (definite proportions) expressed by their 
atomic weights. The formula for the molecule of water is 
H^O, for hydrochloric acid, HOI. The latter may be made 
by inducing chemical union between the constituent ele- 
ments; this union may be thus recorded : H^ + Cl^ = 2H01, 
and such a series of formulas is called an equation. An 
equation is, therefore, the illustration by means of sym- 
bols of the chemical union or resolution of atoms or 
molecules. 

We say chemical resolution, for it is just as possible to 
resolve a compound into its constituent elements as it is to 
cause elements to unite. 2HC1 = H^ -f- Cl^ would be an 
equation illustrating chemical resolution. In all equations 
the kinds and numbers of atoms to the left of the sign of 
equality must always equal those to the right of it. 

It may be appropriately mentioned here that chemical 
resolution is also termed analysis, and chemical union, 
synthesis. Analysis and synthesis have usually given to 
them a broader significance. Analysis does not necessarily 
mean alone to break up compound substances into their 
elements, it means also that a complex combination may 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 19 

be broken up into two or more simpler ones. Chemical 
processes and methods by which we recognize an element, or 
a group of elements, are termed chemical analyses, whereas 
chemical synthesis is the putting together, by means of 
chemical force, elements to form compounds, or uniting 
simpler compounds to form more complex ones. 

By heating mercuric oxide, HgO, the two elements be- 
come dissociated. The analysis may be thus expressed: 
2HgO + heat = Hg^ + O^. This is one form of analysis; 
another may be illustrated by heating calcium carbonate: 
CaCOg + heat == CaO + COj. In the former the product 
of the analysis is the elements; in the latter, compounds 
which are simpler than the one they made up, 

A simple form of synthesis is illustrated by bringing 
iodine and iron in contact for some time — iodide of iron is 
formed according to this equation : Fe, + 2I3 = 2FeIj. 
Another form of synthesis in which simple compounds are 
employed may be symbolized in this equation: SO^ + H,0 
= H2SO3. The sulphur dioxide unites with the hydrogen 
oxide, water, to form sulphurous acid. 

Much more, for which the student is not yet ready, will 
be said about chemical notation and chemical nomencla- 
ture as the student advances. 

The functions of symbols, formulas and equation may 
be briefly summarized : 

A symbol is: (1) shorthand for the name of the element 
which it represents; (2) it represents one atom of that 
element; (3) one volume of that element in the gaseous 
condition; (4) it means a definite chemical proportion or 
atomic weight. 

A formula gives (1) the names of the elements in the 
molecule; (2) the number of atoms in the molecule; (3) 



20 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

the molecular weight or sum of the atomic weights; (4) it 
represents two volumes of the substance in state of gas, 
and (5) denotes that the atoms in the molecule are united 
by chemical force. 

The function of an equation is to express by symbols the 
changes that take place among atoms and molecules in 
analysis or synthesis. 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 21 



The Non-metallic Elements. 

Before entering upon the study of the non-metallic ele- 
ments it is advisable for the student to review all he has 
studied up to the present time, so as to insure a thorough 
understanding of that which is to follow. It is imperative 
to have a good foundation to build upon, and it will be 
well worth the student^s time to read over several times the 
principles of chemistry considered in previous pages. 

The physical differences between non-metals and metals 
are obvious. Every one knows that iron and silver are 
metals. We can tell by their appearance, weight and 
lustre. It is just as obvious that the constituents of the 
air, oxygen and nitrogen, are not metals, and because they 
are not metals we call them non-metals. There is, how- 
ever, no very clear line of distinction in Nature between 
these two subdivisions of the elements as they pass gradu- 
ally into each other. The metalloids^ bismuth, arsenic and 
antimony, may be classed in either division. They are 
called metalloids because they are like the metals in some 
respects. 

Oxygen. 

History. — It is appropriate that we begin the study of 
the chemical bodies with the most remarkable and impor- 
tant element — oxygen. It was discovered simultaneously in 
1774 by Dr. Priestley, of England, and a young apothecary 
by the name of Scheele, in Sweden. Lavoisier, the distin- 
guished French chemist, proved the identity of the gas dis- 
covered by Priestley and Scheele, but did not discover it, 
as is stated by some. Priestley was one day concentrating 



22 PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 

the sun^s rays by means of a burning glass, and directed 
the focus upon some red oxide of mercury, when, to his 
surprise, the oxide began to resolve itself into a gas and 
metallic mercury. The gas was afterward proven to be an 
element. Scheele, about the same time, heated a quantity 
of dioxide of manganese — a stone occurring abundantly in 
the locality of his home, and called hraunstein, i.e., brown- 
stone — with a result similar to that which Priestley had ob- 
tained. It is remarkable that this gas should have been 
discovered by two different men, independent of one 
another, at the same time. The discovery of oxygen marked 
the beginning of the development of chemical science — it 
was, indeed, the birth of chemistry as a science. It was the 
beginning of the unveiling of Nature^s most hidden secrets 
— the deliverance of chemistry from the bondage of the 
ridiculous, pretended science of alchemy. 

Occurrence in Nature. — Oxygen occurs everywhere in 
Nature. The three kingdoms are largely made up of it. 
It is the most widely-distributed and the most abundant 
element we have. The universe is computed to be made 
up of : 

Oxygen 48 per cent. 

Silicon 36 

Aluminum 6 

Calcium 






together 9 



Magnesium 

Sodium 

Potassium 

Iron 

The rest of the elements 1 



100 per cent. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 23 

Water is 88 per cent, oxygen; air, 20 per cent. Fifty per 
cent, of all the rocks is oxygen; from 60 to 80 per cent, 
of plants and animals is oxygen. In short, it is present 
almost everywhere and in everything. 

We know that oxygen is continually being produced 
by plants, these taking in the carbonic acid gas present in 
the air, resolving this into its constituent elements, carbon 
and oxygen, retaining the former and fixing it in their 
tissue, and liberating or setting free the oxygen. 

Preparation. — It may be prepared to-day as Priestley 
and Scheele prepared it over a century ago. By heating 
mercuric oxide it is readily obtained, according to this 
equation: 

Mercuric oxide. Mercury. Oxygen. 

2HgO + heat = Hg, + 0, 

It may be heated in a test-tube with a perforated cork 
inserted, through which a bent glass tube passes, to afford 
a means of collecting the gas as it is generated. To collect 
the gas it is necessary to pass it into an inverted vessel, as 
a bottle filled with water, the mouth of the bottle being 
under water. The gas will pass upward and displace the 
water — that is, it is collected over water. Heating dioxide 
of manganese will produce the same result, according to 
this equation : 

Dioxide of Tetroxide of 

manganese. Manganese. Oxygen. 

3MnO, -f heat = Mn,0, + 0, 

A more ready method is heating chlorate of potassium, 
contained in a test-tube or other suitable apparatus with 



24 PHARMACEUTICAL AKD MEBICAL CHEMISTRY. 

the necessary fitting. This equation expresses the libera- 
tion of oxygen by this method : 

Potassic chlorate. Potassic coloride. Oxygen. 

2KCIO3 + heat = 2KC1 + 30, 

In the latter method less heat is required than in either 
of the former two, but care must be exercised because of 
the explosiveness of the chlorate. 

If the chlorate is mixed with an equal weight of dioxide 
of manganese the evolution of oxygen occurs at a very low 
temperature, so that very little heat is required. In this 
mixture the dioxide of manganese does not yield any gas, 
as it decomposes at a much higher temperature; it acts by 
its presence only. Such substances, which take no part in a 
change like the above, are sometimes said to act by cataly- 
sis — that is, by their presence only. Their presence 
furnishes angles, and angles always facilitate the escape of 
gases. 

Physical Properties. — Oxygen is a colorless, invisible gas, 
without odor, weighing 16 times as much as hydrogen, 
wherefore its atomic weight or specific gravity is 16. Its 
molecular weight is 32 — twice its atomic weight. It has 
been liquefied by extreme pressure and reduction of tem- 
perature. It is soluble to the extent of 5 per cent, in 
water. This 5 per cent, sustains the life of fishes. 

Chemical Properties. — Oxygen has such chemical affinity 
that it combines with every element with the exception of 
fluorine. It oxidizes all the elements. The act of com- 
bination is called oxidation, and the products formed, 
oxides. If carbon, sulphur or phosphorus be burned in 
oxygen, the resulting oxides, 00^, SO, and PjO^, when dis- 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 25 

solved in water form the corresponding acids, carbonic, sul- 
phurous and phosphoric, thus: 

00, + H,0 = H,003 

SO, + H,0 = H,S03 

P,0, + 3H,0 = 2H3PO, 

This fact was noticed by the early experimenters, and be- 
lieving they had found the " acid generator," they gave it 
the name "oxygen," which means "acid generator." 
Later chemists learned, though, that it is not oxygen but 
hydrogen (which means " water generator ") which is the 
essential constituent of acids. 

Burning is a chemical process, oxidation, in which the 
chemical union between the burning body and oxygen is so 
intense that heat and flame are evolved. The more rapid 
and complete the oxidation the more luminous is the flame 
produced. Such a form of oxidation is termed combustion. 

Substances which burn in air burn with more brilliancy 
in oxygen, which fact is employed in recognizing oxygen. 
A glowing piece of wood is instantly relighted into a bright 
flame in oxygen. Oxygen is the supporter of life; taken in 
through the lungs it causes the slow combustion of various 
organic substances in the living animal. It slowly oxidizes 
these bodies, which are mainly refuse, changing them into 
gases, which are eliminated during exhalation. 

It is not necessary for the oxygen to be in its elementary 
condition to enter into combination or to oxidize bodies. 
Some substances contain the oxygen so loosely combined 
that they readily part with it when they come in contact 
with bodies capable of being oxidized. 

The symbol for oxygen is 0; atomic weight, 16; molec- 
ular weight, 32. 



26 PHARMACEUTICAL AIS'D MEDICAL CHEMISTRY. 

Uses and Compounds in Pharmacy and Medicine. — There 
are no direct uses for oxygen in pharmacy, excepting that 
it is kept in some pharmacies for physicians' use. Its 
compounds with other elements receive attention under the 
mineral acids and elsewhere. 

Tests and Experiments. — When things burn in air they 
take up or unite with oxygen. Coal, when it burns, takes 
up or unites with the oxygen of the air, forming carbonic 
acid gas, thus: C^ -1- 20^ = 200^. This equation repre- 
sents all the usual forms of combustion, and combustion 
is generally defined as the union of an element (usually 
carbon) with oxygen, with the production of a flame. The 
products of such combustion are oxides. It must be 
remembered that one-fifth of the air is oxygen, and that if 
combustion takes place with such an amount of oxygen, it 
will be very much more intense in pure oxygen. All sub- 
stances which burn in air burn with very greatly increased 
brilliancy in the pure gas. If we should introduce a glow- 
ing piece of wood into oxygen, prepared as above, it would 
immediately relight and burn with extreme vividness. 
Charcoal, which ordinarily only glows, burns with a very 
bright fiame in oxygen, forming CO^, carbonic acid gas; 
sulphur gives a beautiful blue flame, forming sulphur di- 
oxide (gas), SO^; phosphorus burns with a blinding bright- 
ness in oxygen, producing phosphoric oxide, PjOj iron 
burns with beautiful scintillations, forming ferric oxide, 
Fe^Oj. Substances ordinarily incombustible in air burn with 
surprising brilliancy in oxygen. In all these cases the effects 
are due simply to the union of the burning body with the 
oxygen, forming oxides. This union is in obedience to the 
laws of chemical union already depicted, and if we would 
weigh the bodies and the oxygen in each case, we would 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 27 

find these laws verified experimentally. These experiments 
are all oxidations, and the products formed oxides. 

Ozone. 

Ozone is a peculiar modification of oxygen. If a series 
of electric discharges is passed through oxygen the latter 
becomes modified in a manner that makes ozone of it. 
Ozone is an allotropic (another form) form of oxygen, a 
form which is sometimes designated as the active state of 
oxygen, while the ordinary oxygen is in the passive state. 

Ozone has a characteristic odor, especially noticeable 
after electrical discharges. Oxygen becomes diminished 
in volume if a number of electric discharges are passed 
through it, and experiments have proved that ozone is one 
and a half times as heavy as oxygen, three volumes of 
oxygen becoming two volumes of ozone. The atomic 
weight of ozone is correspondingly found to be 24, oxygen 
being 16; or the molecule of ozone may be looked upon as 

containing 3 atoms of oxygen 0.^ = / \ while the mole- 

0—0 
cule of oxygen contains only 2 atoms, 0, = — 0. 

Ozone has very marked oxidizing properties, exceeding 
those of oxygen. It occurs in the air to some extent and 
may be detected in it by its power to liberate iodine from 
potassium iodide by oxidizing the potassium. For this ex- 
periment white filtering-paper may be saturated with solu- 
tion of potassium iodide containing a little boiled starch. 
The dry paper when it comes in contact with ozone becomes 
blue, owing to the liberation of iodine from the potassium 
iodide, and the reaction ensuing between the iodine and 
starch, which produce the blue iodide of starch. Other 



28 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

gases exercise this same oxidizing effect (e.g., the oxides of 
nitrogen, and hydrogen dioxide). Ozone may be distin- 
guished from these in that it is converted into ordinary 
oxygen when passed through a heated tube, which is not 
the case with the other oxidizing gases. Ozone is also 
produced when strong sulphuric acid acts upon potassium 
permanganate, or when phosphorus is slowly oxidized in 
moist air. 



Hydrogen. 

History. — Hydrogen was discovered by Cavendish in 
1766, who also was first to describe it as an element and to 
prove that it was a constituent of water. By some it is 
stated that Paracelsus obtained it in the sixteenth century, 
but Cavendish first recognized its elementary nature. 

Occurrence in Nature. — Hydrogen is never found free, 
on account of its intense chemical affinity, but in count- 
less combinations it exists widely distributed in Nature. 
it forms one-ninth by weight of water; with nitrogen it 
forms ammonia, NH3, which is of considerable pharma- 
ceutical importance; it constitutes a large proportion of 
all organized bodies, and it is found in products of decom.- 
position, in shooting stars and in volcanic gases in the free 
state, but does not remain so long, usually combining with 
the oxygen in the air. 

Source. — The usual source of hydrogen is water, from 
which it is obtained in various ways, some of which are 
described in the following paragraphs. 

Preparation. — If an electric current is passed through 
water it effects a decomposition of the water according to 
this equation : 2B.fi -\- electricity = 2Hj -}- O^. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 29 

Sodium and potassium as elements also effect the decom- 
position of water, with liberation of hydrogen and forma- 
tion of hydroxides of the respective bases, thus: 

Na, + 3H,0 = 2NaOH + H, 
K, + 2H,0 - 2K0H + H, 

A third and the most convenient method of preparing 
hydrogen is by means of zinc and hydrochloric or sulphuric 
acid: Zn, + 2H,S0, = 2ZnS0, + 2H,. 

The zinc, preferably in form of granules, is introduced 
into a small flask into which is fitted a rubber stopper, 
through which passes a glass tube, bent at right angles just 
as it leaves the stopper. The tube should terminate in the 
flask just below the lower end of the stopper, and should 
be drawn to a point at its other end. When the sulphuric 
acid (diluted) comes in contact with the zinc the evolution 
of hydrogen begins, the gas finding its exit through the 
tube. It may, like oxygen, be collected over water. The 
zinc in the flask becomes dissolved, forming sulphate of 
zinc. 

There are many other methods for preparing hydrogen, 
but this is the one usually employed for experimental pur- 
poses. 

Physical Properties. — Hydrogen is a colorless, odorless, 
invisible gas, very inflammaMe, and slightly soluble in 
water. It is the lightest of all known bodies, and is there- 
fore employed as the standard of comparison for the atomic 
weights of all the elements. It is an exceedingly diffusive 
gas, more so than any other; it will escape through joints 
of apparatus which are impervious to other gases. It is well 
to remember that all gases are diffusive, and that they dif- 
fuse in inverse proportion to the square root of their 



30 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

sity or specific gravity. Thus oxygen, having a specific 
gravity or density of 16, will diffuse but one-fourth as fast 
as hydrogen: 

= 16, of which the square root is 4; 
H = 1, of which the square root is 1 ; 

or^ in other words, hydrogen diffuses four times as fast as 
oxygen. On account of its extreme lightness it is some- 
times used for inflating balloons. Hydrogen is a non-sup- 
porter of combustion, but combustible itself. It will not, 
like oxygen, support life. 

Chemical Properties — Tests and Experiments. — If the 
hydrogen, prepared as above from zinc and sulphuric 
acid and passed through the glass tube, be brought in con- 
tact with an ignited match it will burn with a yellowish, 
nearly non-luminous, but very hot flame. (Care should be 
taken that all the air has been expelled from the flask to 
prevent explosion.) This flame is due to the chemical 
combination of hydrogen with the oxygen in the air, form- 
ing water in this wise: 2H2 -)- 0^ = 2H2O. When hydro- 
gen burns it always produces water. There is a very strong 
affinity between these two gases, and if mixed in any 
quantity and ignited, violent explosion taken place. In 
the above experiment only a small portion of hydrogen 
comes in contact at a time with oxygen. The oxy -hydro- 
gen blowpipe is an arrangement whereby two volumes of 
hydrogen are made to meet one volume of oxygen at a 
point which is the terminus of two tubes conveying the 
two gases in proper proportions to form water. These pro- 
portions are the most economical, and produce greatest 
heat and light; but they may vary within wide limits. 
The union of the two gases produces a very high tem- 



PHARMACEUTICAL AI^D MEDICAL CHEMISTRY. 31 

perature, one hot enough to melt iron or almost anything. 
This is a vivid illustration of the intensity vrith which 
chemical combination sometimes takes place. 

If soap-bubbles be blown from a bag containing a mix- 
ture of 2 parts hydrogen and 1 part oxygen, and touched 
with a match or a candle, they explode with a detonation 
like that of a pistol-shot. Chemical union is not always 
spontaneous; in this, as in some other cases, it is 
necessary to employ an inducing-agent, the flame in this 
case. 

If a jar be filled with hydrogen and held with the mouth 
downward the hydrogen will not escape very readily. A 
lighted candle introduced into the jar will become extin- 
guished, while the hydrogen will burn at the mouth of the 
jar. The candle may be withdrawn, when it will relight, 
becoming extinguished a second time if introduced into the 
jar again. This shows hydrogen to be inflammable hut not 
a supporter of combustion. 

A great amount of chemical energy is possessed by 
hydrogen; one part of it by weight will neutralize 35.5 of 
chlorine, 80 of bromine and 126 of iodine, or as much of 
any of the elements by weight as is represented by their 
atomic weights divided by their quantivalence. It will 
extinguish, therefore, 16 of sulphur — the atomic weight of 
sulphur being 32, this divided by its quantivalence, 2, in 
this case, giving 16. 

Hydrogen is the base in all acids, and may be replaced 
in them by the alkalies or metals to form salts. In hydro- 
chloric acid, HCl, the hydrogen may be replaced by sodium, 
Na, to form sodium chloride, NaCl. Potassium bromide, 
KBr, as a further illustration, is hydrobromic acid, HBr, 
in which the H is replaced by potassium, K, 



32 PHARMACEUTICAL A^-D MEDICAL CHEMISTRY. 

Is Htdrogen^ a Metal ? — We are treating of hydrogen 
now as among the non-metals. It has long been a ques- 
tion whether it is a metal or a non-metal. Many of its 
chemical properties would class it with the metals, but its 
physical properties would place it among the non-metals. 
Some chemists suggest that it is a metal which exists 
at the prevailing temperature in the form of a gas, and 
that if the temperature could be reduced far enough it 
might be obtained in the form of a liquid or solid. In 
view of this and the analogy of its behavior to the other 
metals, many accept hydrogen as a metal. It is here 
studied among the non-metals for convenience. 

In the beginning of this course the student learned that 
all bodies exist in one of the three forms — gaseous, liquid 
or solid — and that the condition depends upon the pre- 
dominance of one or the other of the molecular forces, 
cohesion and repulsion. It is appropriate to mention 
here that these molecular forces are in their turn de- 
pendent upon the temperature, heat destroying or les- 
sening the cohesive and increasing the repulsive force, 
cold increasing the cohesive and lessening the expansive 
force. 

Different bodies are differently affected by different tem- 
peratures, mercury, for example, being liquid at 32° F., 
while water becomes solid at that temperature. 

Uses in Pharmacy. — There are no specific uses in phar- 
macy for hydrogen, excepting perhaps its employment 
in some chemical processes, as in the preparation of re- 
duced iron from ferric hydroxide, etc., or in the application 
of tests for the purity of some of the pharmacopoeial 
products. 

Compounds, — Of the compounds of hydrogen water 



PHAKMACEUTICAL AKD MEDICAL CHEMISTRY. 33 

ranks first and the acids next, the carbohydrates and 
hydrocarbons (unions with carbon), in the organic world, 
following. It forms hydrides with some of the elements 
— PH3, AsHg, SbHg — though it is contended by some that 
the term is not correctly expressive of the form of combina- 
tion. It is preferred to call these combinations, PH3, phos- 
phoretted hydrogen; AsHg, arseniuretted hydrogen, etc. 
With oxygen it forms, besides water, another compound, 
H3O2, the hydrogen dioxide or peroxide of hydrogen. The 
prefix 'per meajis liigli, above, to the fullest extent, and hence 
2i, peroxide is a combination containing more oxygen than 
another compound containing the same elements: H^O, 
water, is an oxide of hydrogen; H^O^, containing more 
oxygen, is the peroxide. The same applies to other ele- 
ments besides oxygen — there are perchlorides, persulphates, 
etc. 

Hydroxides — often called hydrates — are also compounds 
containing hydrogen; they are usually looked upon as 
water, H,0, H — — H, in which one of the hydrogen 
atoms is replaced by some other element or base. Potas- 
sium hydroxide would be K — — H, the K taking the 
place of one of the hydrogen atoms. 

Water. 

Water being an oxide of hydrogen, it is appropriate to 
treat of it under hydrogen. 

The importance of water in the economy of nature must 
be apparent to all, in that it is one of the essentials in the 
maintenance of all living things — without it there could 
be no life. It is the most abundant substance in nature 



34 PHAEMACEUTICAL A1S"D MEDICAL CHEMISTRY. 

and in its changes of form from the solid ice to its invisi- 
ble vapor involves the very history and destiny of the 
earth. Water is concerned in the majority of chemical 
processes, and is as indispensable in the laboratory of the 
chemist as in that of Nature. The indispensability of 
water was apparent to the ancients, and we readily excuse 
them for having classified water with their elements, which 
we all know to have been air, fire, earth and water. The 
elements of the ancients were supposed to be transforma- 
ble one to the other; it w^as believed that water could 
be changed to earth, and vice versa, until a chemist dis- 
proved that belief by distilling and redistilling a weighed 
quantity of water in air-tight stills and condensers for 
more than 100 days, at the end of which time he found 
that the water had not lost weight nor volume. He em- 
ployed distilled water, which had not been done by others, 
they always having obtained a residue which was com- 
posed of the fixed matter present in all waters, but which 
they supposed to be transformed water. 

Composition. — Water is composed of 8 parts by weight 
of oxygen and 1 part of hydrogen, or, by volume, of 2 of 
hydrogen and 1 of oxygen; its composition is expressed by 
the formula H^O. That this is so may be proven in sev- 
eral ways, the simplest being the decomposition of water 
by the electric current. The water is contained in an 
apparatus so arranged that the two gases are set free 
in separate graduated tubes, which are filled with water. 
The volume of each gas may be read olf, after decom- 
position, and will be found to be twice as great for the 
hydrogen as for the oxygen. If the gases, in the exact 
proportion as given ofi, are mixed and ignited they will 
combine with a loud explosion, reforming pure water. 



PHAKMACEUTICAL AND MEDICAL CHEMISTRY. 35 

We have thus two methods of proving the composition of 
water — the one by analysis, the other by synthesis, or 
" putting together/' 

If metallic sodium or potassium be thrown upon water 
the latter will decompose with such violence as to produce 
a flame, usually. The oxygen which is liberated seizes 
upon the metal and forms its oxide, the oxide uniting 
with water to form the hydroxide : 

Sodium. Water. Oxide of sodium. Hydrogen. 

Na, + H,0 = Na,0 + H, 

Na^O + H,0 = 2NaOH, Sodium hydroxide. 

Iron, or zinc, when heated to redness, has the same 
action on water. 

A process upon which much reliance can be placed for 
demonstrating the composition of water is that in which 
pure oxide of copper is reduced by hydrogen, and the 
water so formed is collected and weighed. 

Copper oxide. Hydrogen. Water. Copper. 

CuO + H. = H,0 -r Cu 

By noting the weight of the oxide of copper before and 
of the copper after the operation, weighing the hydrogen 
and finally the water, we can tell the composition by 
weight of the water formed. 

The elements of water are separated and reunited in 
numberless operations in chemistry, and the same thing is 
going on continually in plants and animals. Indeed, water, 
constituting four-fifths of the vegetable kingdom and 
three-fourths of the animal, is the prime .condition of all 
organization, and the maintenance and continuation of or- 



36 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

ganic life are largely dependent upon its many transfor- 
mations and decompositions. 

General Properties. — Water is a colorless, transparent, 
tasteless, inodorous, volatile liquid, or solid if the tempera- 
ture is below 32° F. It is practically incompressible. It 
evaporates spontaneously at ordinary temperatures, boils 
at 212° F. (100° C), and freezes at 32° F. It does not ex- 
pand or contract equally, having its maximum density at 
39.2° F. (4° C), and expanding 10 per cent in becoming 
ice. The weight of 1 c.c. at that temperature is 1 gramme, 
which is the standard of weight in the metric system. 
A cubic inch of water weighs at ordinary temperature 
252.45 grains, whereas a cubic foot weighs about 1000 
avoirdupois ounces. Water in small bulk is colorless, but 
in mass it is blue, like the atmosphere. The admixture 
of the slightest quantity of some substances destroys the 
color. 

Water never occurs in nature in a state of absolute 
purity. It always contains some dissolved matter, usually 
saline, sometimes organic. 

All natural waiers contain in solution the hicarhonates, 
chlorides and sulphates of sodium, potassium, calcium, 
magnesium, and often iron and silica. The only absolutely 
pure water is that obtained by distillation. Rain-water, 
even, evaporated from the sea and condensed in the air, 
descending through the atmosphere, becomes charged with 
the soluble impurities present in the air, such as am-, 
monia, carbonic acid gas, etc., and hence is not absolutely 
pure. 

Chemical Properties. — Water forms hydroxides when 
brought in contact with many of the oxides, the combina- 
tions being in some instances so intense that considerable 



PHARMACEUTICAL AND MEDICAL CHEMISTET. 37 

heat is evolved. The hydroxides contain the hydrogen 
and oxygen in the proportion to form water, but they do 
not exist as water, the atoms suffering a change of arrange- 
ment during the union with the bases. Thus, caustic 
potassa, KOH, or potassic hydroxide, may be looked upon 
as being composed of K,0 + H,0 {= 2K0H). 

Sodium hydroxide, 2NaOH, is Na^O and H^O 
Calcium hydroxide, Ca(0H)2, is CaO and H^O 

The water is retained in these compounds with such 
tenacity, that a high heat is necessary to remove it. In 
case of calcium hydroxide it requires a red heat to expel 
the water and convert it into the oxide again, while in 
many other instances the water is held with such force 
that it cannot be expelled by heat at all. 

The term hydrate is often used for hydroxide, but it 
should not be, as hydrate has another specific meaning. 
Hydrates are bodies, salts, for example, which unite with 
water without causing an alteration of atomic arrange- 
ment. The water in such combinations is termed ivater of 
crystallization, and may be easily removed by compara- 
tively low heat. Sodium carbonate, for example, has ten 
molecules of water, which latter may be said to be in 
juxtaposition to the sodium carbonate, and which can be 
separated without altering the composition of carbonate 
proper. The formula is J^a^COg . lOH^O. Heat will re- 
move the lOH^O, leaving the Na^COj. 

Salts which do not contain any water of crystallization 
are anhydrous, so common salt, sodium chloride, NaCl; 
potassium chlorate, KCIO3, etc., are anhydrous. Cryohy- 
drates are hydrates which exist only at temperatures below 



38 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

the freezing point. Sodium chloride, which at ordinary 
temperatures is anhydrous, becomes a cryohydrate when 
solidified at about 40 degrees below the freezing point, 
when it has this formula, 2NaCl . 2IH2O. 

When the water of crystallization is so feebly united 
with the salt that it gradually separates at the ordinary 
temperature, the salt is said to be efflorescent, and the 
change is called efflorescence. Sodium carbonate crumbles 
because it is efflorescent — that is, the water is instrumen- 
tal in the formation of crystals, which lose their shape 
when the water is expelled, or when it separates spontan- 
eously. 

On the other hand, some bodies take up water from the 
air and become liquefied; such bodies are said to be deli- 
quescent, and the change is called deliquescence. Calcium 
chloride is a good example of a deliquescent salt. 

Water is the very best solvent we have. As a rule, salts 
are more soluble in hot water than in cold ; notable excep- 
tions are common salt, which is equally soluble in water 
at any temperature, and many calcium salts, which are less 
soluble in hot than in cold water. Water dissolves many 
of the gases, and therefore also the air, to some extent, but 
the air dissolved in water has not the same composition as 
that constituting the atmosphere, which is one-fifth oxygen 
and four-fifths nitrogen. This is because the oxygen is 
much more soluble in water than the nitrogen. 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 



39 



Natural "Waters. 

These may for convenience be divided into two classes, 
the atmospheric and the terrestrial, and these classes still 
further subdivided, thus: 



Ltmospheric. 


Terrestrial. 


Eain 


Ocean ) 


Snow 


Seas V Sa 


Hail 


Lakes 


1 


Fog 


Lakes 




Dew 


Rivers 




Watery vapor 


Creeks 


^ Fi 




Brooks 


> J: 1 




Springs 






Wells , 





Atmospheric Waters. — Of the atmospheric waters we 
need not say much. They are all the result of the con- 
densation of the water evaporated from the surface of the 
earth. 

The great specific heat of water has a powerful control- 
ling influence on the climate. Perhaps the student does 
not know what specific heat means, and a brief exposition 
of it may be in order. Equal weights of different bodies 
at the same temperature require different amounts of heat 
to raise them to a given degree of temperature. A certain 
amount of heat is required, for example, to raise 1 pound 
of water at 100° to 101°; that amount is not the same for 
all bodies, but varies for every body. The amount of heat 
required to raise a body one degree in temperature, com- 
pared to the amount of heat required to raise an equal 
weight of water through 1°, is that body's specific heat. 
There are several methods of obtaining the specific heats 
of bodies. If 1 pound of water having a temperature of 



40 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

100° be mixed with 1 pound of Avater of 40°, the 2 pounds 
will have a mean temperature of 70° : 100 -f 40 = 140, 
-f- 2 = 70. The first pound of water gives 30° to the water 
of 40°, making i^hat and becoming itself 70°. This is true 
if equal portions of any one liquid of different temper- 
atures are mixed, but if unlike bodies having different 
temperatures are mixed, a mean temperature does not 
result. 

If 1 pound of water of 100° is shaken with 1 pound of 
mercury at 40°, then, these being unlike bodies, instead of 
a mean temperate of 70°, the temperature will become 98°. 
The water lost 2°, an amount sufficient to raise the tem- 
perature of an equal weight of mercury 58°; that is, from 
40° to 98°. It is evident from this that the specific heat 
of mercury is only -f^, if water is 1. In the first case the 
30° of heat which the 100°-water lost raised the tempera- 
ture of water of 40° to 70°, or every 1° of heat from the 
water of 100° raised the water at 40° 1°, but in the second 
case, since the 2° which the water lost were sufficient to 
raise the pound of mercury through 58°, to raise mercury 
through 1° would require -f-^ as much heat as water re- 
quires. 

Water has the highest specific heat of any body known. 
The stability of Nature is dependent upon this high spe- 
cific heat of water. Were it not so, the rapid changes 
in temperature which would ensue would unfit this globe 
for habitation. If water could acquire heat with as much 
facility as mercury does, the seas and water everywhere 
would freeze and thaw so rapidly and often that all living 
things would perish from want of adaptation. 

Terrestrial Waters include all that are on or in the 
earth; they are divided into the salt and fresh waters. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 41 

The ocean, inland seas and some lakes are salt, while all 
the other divisions are fresh; that is, without salt. The 
fresh water is further classified into soft and liard water. 

Hard Waters. — As we have learned, all natural waters 
contain dissolved matter; this is especially true of terres- 
trial water, which, while traversing the surface or interior 
of the earth, becomes charged with the soluble portions of 
whatever it comes in contact with. If the water contains 
carbonic acid gas, CO^, its property of dissolving certain 
bodies is increased. All rocks are soluble to a slight ex- 
tent in water, but those containing lime, magnesia or iron 
are more soluble in water containing carbonic acid gas. 

A water which happens to contain carbonic acid gas 
freely dissolves limestone, which is calcium carbonate, by 
converting it into the soluUe hicarlonate : 

Calcium Carbonic Calcium 

carbonate. acid. bicarbonate. 

CaC03 + H,C03 = CaH,(C03), 

Such water would be called a lia7'd water. Water also dis- 
solves out of the rocks and soil the sulphate of calcium, 
CaSO^, and thereby becomes another variety of hard water, 
known as permanently hard, while the former, containing 
the bicarbonate of calcium, is termed temporarily hard. 
These terms express the nature of the water relative to the 
kind of calcium salt present. Because we can remove the 
hardness of the water containing the bicarbonate in solu- 
tion, it is called the temporary hardness, while if due to 
the sulphate it is ^erm«?^e?^^, because it cannot be remedied. 
The temporary hardness of water may be removed by 
boiling or by adding lime-water, a solution of Ca(0H)2 as 
shown by the following equations : 



42 IPHARMACEtJllCAL AKt> MEDICAL CHEMISTRY. 

Calcium Calcium Carbonic 

bicarbonate. carbonate. Water, acid gas. 

CaH,(C03), + heat = CaC03 + H,0 + CQ, 

Calcium 
hydroxide. 

CaH,(C03), -h Ca(OH), = 20^00, + 2H,0 

The soluble hicarlonate becomes the insoluble carbonate 
in both instances, and this precipitates, and in so doing ren- 
ders the water soft, for the hardness is caused only by the 
calcium salt being in solution. The use of soap with such 
water is attended with great loss of soap in the chemical 
change which takes place in the endeavor to form a lather. 
Soap with soft water gives a lather at once, but with hard 
water only after all the calcium salt has been converted 
into the insoluble calcium soap. The following equations 
will illustrate the change : 

Soluble Soap — Sodium. Insoluble Calcium Soap. 

Sodium palmitate, 2NaCi6H3i- ) (Calcium palmitate, CaCCieHa 



O2, -f- calcium bicarbonate, )■ = ■{ 02)2, + sodium bicarbonate, 
CaH2(C03)2 ) ( SNaHCOs. 

Sodium oleate, 2NaC:sH3302, ) ( Calcium oleate, Ca(Ci8H3302)2, 
-|- calcium bicarbonate, Ca- > = \ + sodium bicarbonate, 2]Sra- 

H2(C03)2 ) ( HCO3. 

Sodium stearate, 2NaCi8H3502, i i Calcium stearate, Ca(Ci8H35, 
+ calcium bicarbonate, Ca- > = \ 02)2, + sodium bicarbonate- 
H2(C03)2 ) ( 2NaHC03. 

Ordinary soap is a chemical compound consisting of 
three definite salts — the palmitate, oleate and stearate of 
sodium, which, with the soluble lime salt, become con- 
verted into the corresponding calcium salts, which are 
insoluble. The greasy scum which floats on hard water 
which has been treated with soap, is the light and insoluble 
calcium soap, which gives to the touch the sensation of 
hardness, whence the name. 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 43 

Mineral Waters. — We have learned, and it is worth re- 
peating, that all natural waters contain dissolved matter, 
and that spring-water, especially, always contains the 
chlorides, sulphates and bicarbonates of sodium, potassium, 
calcium, magnesium and sometimes iron and silica. A 
mineral luater is one which contains one of these usual 
constituents in an abnormal or unusual quantity or a sub- 
stance which is not usually found in natural waters. All 
the mineral waters scattered over the earth are simply 
spring waters impregnated, to a greater or less extent, with 
soluble, substances to which medicinal virtues are attributed. 
Some waters hold carbonic acid gas in solution, when they 
are termed sparkling or effervescent, while those without 
that gas are termed still. When iron is present the water 
is known q,% ferruginous or chalybeate; others are alhaline, 
while some are acid. Borax waters are so called because 
they contain borax, while the name alu7n water is due 
to the presence of alum in such waters. When much 
sulphate of sodium (Griauber's salt) is present, or sulphate 
of magnesium or other salt, we term the water saline. 
Sulphur ivaters are so called because they contain sulphur, 
usually in the form of soluble sulphides. Others contain 
notable quantities of iodine, some bromine, others arsenic, 
still others lithia, etc. 

Most of these mineral waters must be used as they are 
taken from the springs, but a number of them may be 
evaporated to a small bulk. 

Well-water. — Wells, unless situated distant from habi- 
tations, may become dangerous. The soil in which they are 
dug or driven is usually pervious, so that they may become 
contaminated with anything with which water trickling 
from the surface through the soil into them may come in 



44 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

contact. Decaying organic matter, the refuse from stables, 
etc., are dissolved by the water falling upon them as rain, 
which in its descent through the soil will find its way into 
the well. This organic matter does not necessarily unfit 
the water for domestic purposes; the danger lies in its 
affording a breeding medium for disease germs, which, 
it is well known, develop rapidly when brought into the 
system. 

To test well water or other drinking water for its purity 
comes within the domain of the pharmacist, though a com- 
plete and exhaustive analysis should be referred to a skilled 
chemist. The substances to be looked for primarily are 
organic matter, albuminoid matter, ammonia and nitrates 
and nitrites. The nitrogen compounds are usually more 
abundant if animal matter is present; they, of all other 
constituents, render water the most unwholesome. The 
following tests are given here, but the student may omit 
their application until he will have advanced a little farther. 

1. For Organic Matter, — Color a portion of the sample 
distinctly with a solution of permanganate of potassium 
and add two or three drops of dilute sulphuric acid. If 
much organic matter is present the color of the permanga- 
nate becomes discharged almost immediately; if less, it 
takes a little longer to decolorize. If the color has not 
changed in 20 to 30 minutes it is safe to assume that or- 
ganic matter is not present. This is a tolerably reliable 
test. 

2. For Nitrites. — A little sulphuric acid added to the 
water containing nitrites forms nitrous acid, which is easily 
detected by its power to liberate iodine from a solution of 
iodide of potassium. A little starch paste, made by boiling 
starch with water, is mixed with a solution of iodide of 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 45 

potassium and the whole added to the suspected sample, 
and if nitrites are present the starch will turn blue with 
the liberated iodine. 

This indirect method is a means for detecting nitrites, if 
present in not too small a quantity. 

3. Nitrates are detected by converting into nitric acid, 
which turns morphine red. A portion of the water is 
evaporated to dryness, the residue treated with a drop of 
sulphuric acid, which makes nitric acid of the nitrate, and 
a portion of morphine added. If nitrates are present a 
red color will ensue. 

4. For Ammo7iia. — Nessler's reagent affords by far the 
best test. The solution may be made by dissolving 18 
grains of iodide of potassium in a little water, adding 
solution of mercuric chloride until the red iodide first 
formed redissolves upon agitation. To this are added 50 
grains of caustic potassa, and distilled water to make 8 
ounces. This reagent will detect 0.00375 grain of ammonia 
in a pint of water by giving yellow to reddish color. 

Albuminoid Aimnonia requires a more elaborate process 
for its detection. If all the above were found it is hardly 
necessary to go to the trouble of looking for albuminoids; 
the water would be unwholesome if they were not present. 
If it is required to test for them, nevertheless. Chapman and 
Wanklyn^s test may be employed. If the water was found 
to contain ammonia, this must first be removed, as must 
also any urea that " may be present. This is best done by 
distilling the water until it gives no further reaction with 
Nessler^s solution. Then add a strong solution of caustic 
potassa and potassium permanganate, and examine again 
for ammonia. This test depends upon the fact that caustic 
potassa and permanganate of potassium cause animal mat- 



46 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

ter, while still in an ambuminoid condition, to unite with 
hydrogen to form ammonia. 

These tests are easily applied, but they are only toler- 
ably reliable. If all respond readily, it is quite safe to 
assume that impurities are present. If, however, they do 
not respond satisfactorily, and an important issue is in 
question, the suspected sample should be referred to an 
analytical chemist. 

The Purification of Waters. — Of the methods for purify- 
ing waters we have already become acquainted with those 
for hard water. The best general method is that of distil- 
lation ; all fixed matter remains in the retort, while foreign 
volatile bodies may be dispelled by boiling previous to dis- 
tillation. To render water perfectly pure it should be re- 
distilled in silver vessels. 

Mechanically suspended organic impurities in water are 
noxious, rendering water unwholesome and unfit for do- 
mestic or culinary purposes. It should be stated, however, 
that when these organic impurities are present (they may 
be from the drainage of houses, stables, from decaying 
leaves and animals, from the dust in the air, etc.) they are 
usually attended by a more or less efficient purifying agent 
in the form of animalculae (or little animals), which feed 
upon them. These minute organisms may be viewed 
through a powerful microscope, when they will exhibit 
definite yet hideous shapes. There are about 30 species 
(or more) of them, all performing invaluable service in puri- 
fying water by consuming dead organic matter, reducing 
it to its ultimate harmless constituents — carbonic acid gas, 
ammonia and water. They themselves are harmless, yet, 
where they can exist, the pathogenic or disease-generating 
microbes may also flourish. 



PHAKMACEUTICAL AND MEDICAL CHEMISTRY. 47 

Boiling is a simple means of purifying water; it kills 
animal and vegetable matter (though not all disease germs)^ 
and expels gases. If lime is in solution it becomes precipi- 
tated. 

Turbid or muddy water may be clarified by the addition 
of a little alum (ten grains to a gallon), which forms with 
bicarbonate of calcium, which is usually present, a hydrox- 
ide of aluminum, which in its descent carries the suspended 
matter with it mechanically. 

Filtering through charcoal, sand, felt or brick, or through 
some other porous medium, also deprives water of suspended 
matter. 

If a doubtful sample of water must he used for culinary 
purposes it should ie boiled for half an hour and filtered ; 
any contaminating matter will thereby probably become 
destroyed. 

Peroxide of Hydrogen. 

We leave now the monoxide of hydrogen, or water, to 
briefly consider the dioxide or peroxide of hydrogen, and 
with that will dismiss the compounds of hydrogen. 

Peroxide of hydrogen is, as the name indicates, a higher 
oxide than water, having the formula H^O^; by some it is 
claimed to be a hydrate of oxygen, OH^O. 

It is a transparent liquid, colorless, of a specific gravity 
of 1.006 to 1.012. It volatilizes at ordinary temperatures, 
and when brought in contact with some bodies decomposes 
with violence. It is odorless, has an acidulous taste, and 
possesses pronounced bleaching properties. Because it is 
very unstable, the commercial product has added to it a 
small proportion of a mineral acid, which renders it some- 
what more permanent. 



48 PHARMACEUTICAL AN'D MEDICAL CHEMISTRY. 

It may be made from tlie peroxide of barium, BaO^, by- 
treating with hydrochloric acid: thus, BaO^ + 2H01 = 
BaOlj -|- HjOj. The BaOlj is precipitated with sulphate 
of silver, which produces the insoluble salts, silver chloride 
and barium sulphate, which are removed by decantation. 

The aqueous solutions of the market are known as the 
10 volume and 15-volume products. The 10-volume article, 
which is official in the U. S. Pharmacopoeia, is known by 
that name because it contains 3 per cent by weight of the 
peroxide, which yields ten volumes of active oxygen. The 
oxygen is the active constituent doing the bleaching for 
which the solution is mostly used. The quantity of oxygen 
may be estimated by noting the quantity of acidulated per- 
manganate of potassium which it decolorizes. 

A variety known as the 0. P. solution is used in medi- 
cine and surgery as a powerful antiseptic. Externally it is 
used as an application to ulcers, and as a dressing to all 
kinds of wounds. Its value, of course, depends upon the 
oxygen which it gives off. 

Nitrogen. 

History. — Nitrogen was not discovered until 1772, when 
Butherford isolated a gas which he claimed to be an ele- 
ment, and which claim was subsequently proved to be true. 
At first it had two names given it, one, nitrogen, because 
of its source from nitre ; the other, azote, because it was sup- 
posed to be poisonous, that word meaning without life. 
Animals kept in nitrogen for only a brief time would per- 
ish. We know now that death was not the result of the 
toxic properties of the nitrogen, but the result of the ab- 
sence of oxygen, which latter is the life-sustaining princi- 
ple of the air, 



PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 49 

Occurrence in Nature. — Nitrogen is widely distributed in 
nature, being most abundant in a free condition in the at- 
mosphere, of which it constitutes about four-fifths. It 
plays an important part in the vegetable kingdom, enter- 
ing into many compounds and forming an essential con- 
stituent in others. Alkaloids contain it, as do ammonia 
and nitric acid and all cyanides. It is found, combined 
with potassium, as Calcutta nitre in India, as an efflores- 
cence on the earth^s surface. The Chili nitre, or nitrate 
of sodium, occurs in a like manner on the soil in Chili. 
Some varieties of coal also contain nitrogen. 

Functions in Nature. — The chief function of nirtogen in 
the air is to dilute the more energetic oxygen. It is also es- 
sential to plants, which imbibe it in the form of ammonia. 

Properties. — Nitrogen is a colorless, inodorous gas, with- 
out taste, and from a chemical point of view a very indif- 
ferent body — to combine it with other bodies we must em- 
ploy a very circuitous method. It is incombustible and 
does not support combustion ; a lighted match or taper in- 
troduced into it is immediately extinguished. It has been 
liquefied by Cailletet and Pictet and Dewar; its solubility 
in water is only very slight. It has at times 1 bond, at 
others 3, 5 and even 7; its atomic weight is 14; molecular 
weight, 28; symbol, N. 

Preparation. — It may be prepared in a number of ways, 
but most commonly it is obtained from the atmosphere by 
withdrawing or using up the oxygen in it, leaving the 
nitrogen by itself. 

A small piece of phosphorus floating in water on a small 
porcelain cup is ignited and a jar set over it immediately. 
The phosphorus in burning unites with the oxygen of the 
air, forming phosphoric oxide, ^fi^. The latter is very 



50 PHAKMACEUTICAL AlsTD MEDICAL CHEMISTRY. 

soluble in water and is soon absorbed, leaving compara- 
tively pure nitrogen in the jar. 

Compounds. — With oxygen, nitrogen forms five com- 
pounds : 

ISr^O, nitrogen monoxide or hyponitrous oxide. 

NjOj , nitrogen dioxide. 

N2O3 , nitrogen trioxide or nitrous oxide. 

^fi^ , nitrogen quadroxide or tetroxide. 

NjOj^ , nitrogen pentoxide or nitric oxide. 

Of these, three are capable of uniting with water to form 
acids : 

N,0 + H,0 == 2HN0, hyponitrous acid. 
N,03 + H,0 = 2HN0, , nitrous acid. 
N,0, + H,0 = 2HNO3 , nitric acid. 

The N^O, sometimes called laughing-gas (also, errone- 
ously nitrous oxide), is easily prepared by heating ammo- 
nium nitrate: NH,N03 + heat = 2H,0 + N,0. This is a 
gas of a sweetish taste, colorless and almost inodorous, having 
the characteristic property of producing anaesthetic effects 
upon the system, for which it is employed in dentistry. 

The N^O, is produced when nitric acid is heated to de- 
composition or when it acts upon metals, or whenever it 
acts as an oxidizing agent. Nitric acid is a most power- 
ful oxidizer; it always resolves itself into water, N^O^ and 
oxygen in this wise: 2HNO3 + heat = N,0, + 30 + H,0. 
The oxygen does the oxidizing in combining with other 
bodies. N^O, is colorless, but when it comes in contact 
with the oxygen of the air it unites with it to form the 
tetroxide: N^O, -{- 0^ = N^O^, which is of a reddish color. 

The NjO^ with water forms nitric acid, as shown above. 
Two molecules of N^O^ are sometimes looked upon as being 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 51 

composed of one molecule of N^O and one of 'Nfi^ : 'Nfi 
-\- N2O3 = 2'Nfi^. A similar view is taken by some of 
the composition of the N^O^. The N^Og and N^O^ to- 
gether equal two molecules of N^O^. 

With hydrogen, nitrogen forms ammonia, NH3 , which 
is constantly generated in nature during the decomposition 
of organic matter. The ammonia is also produced by the 
destructive distillation of organic matter, illustrated in the 
manufacture of illuminating gas, which is made by the 
destructive distillation of coal. Ammonia and its salts, 
as well as the acids of nitrogen, will be considered under 
other headings. 

All alkaloids contain nitrogen, as do also cyanogen (ON) 
and its compounds. These will receive attention in their 
appropriate places. Many salts containing nitrogen are 
poisonous; notable exceptions are the nitrates of sodium 
and potassium. 

Test for Nitrates. — If to a portion of strong sulphuric 
acid contained in a test-tube a freshly prepared solution of 
ferrous sulphate is gradually added so that it forms a layer 
above the acid, and a portion of a solution of a nitrate is 
slowly added and the tube gently agitated, a brown zone 
will form between the acid and the iron solution. 

Oxygen and Nitrogen as the Atmosphere. 

The invisible elastic envelope which surrounds the globe 
as a mantle is the atmosphere, the gaseous matter of which 
it is constituted being usually distinguished by the name 
of air. The air possesses no color or taste, nor can it be 
felt or grasped with the hand, yet, notwithstanding, it is 
material. Every one has noticed that when a funnel fits 
very tightly into the neck of a bottle, water poured into 



52 PHARMACEUTICAL AI^D MEDICAL CHEMISTRY. 

it will not run through it into the bottle, the air within 
the bottle finding no outlet, and being material, according 
to the general property of matter termed impenetrability 
(in virtue of which no two bodies can occupy the same 
space at the same time), prevents the water from entering 
the bottle. When the funnel is slightly raised the water 
rushes into the bottle, the air being displaced at the same 
time and rushing out of the bottle. 

Air has weight like all other forms of matter; a globe 
when weighed has a greater gravity than when the air is 
exhausted from it. To exhaust a vessel, a globe, e.g., of 
air, an instrument called an air pump is employed, which 
removes the air more or less thoroughly, causing a vacuum, 
though it is almost impossible to create an absolute vacuum. 
The difference in weight of the flask or globe before and 
after exhausting the air, the volume of its capacity taken 
into consideration, will show the weight of the air which 
the flask or globe will hold. It is thus ascertained that a 
cubic foot of air weighs about 538 grains; a room 40 feet 
square and 18 feet high contains about a ton of air. Air 
compared with hydrogen has a specificgravity of 14.4; water 
is about 825 times heavier than air. It is supposed that the 
air extends about 50 miles upward, although some claim 
only 10 miles, and others even 200 miles; more recent ex- 
periments favor the first-mentioned supposition. It is ob- 
vious that this tremendous ocean of air, at the bottom of 
which we live, must exert a vast pressure upon the surface 
of the earth. 

This pressure amounts to 15 pounds upon every square 
inch of the earth^s surface; it is not only directed down- 
ward, but in all directions — upward, sideward, etc. The 
weisfht of the air is not the same at all times, as it be- 



PHARMACEUTICAL AND MEDICAL CHEMISTEY. 53 

comes condensed or rarified by atmospheric changes in- 
duced by winds, storms, etc. ; it may be conceived to be 
moved by tides which sweep over the earth, and with these 
movements the pressure or weight changes, though never 
very much. The variations in the pressure may be meas- 
ured, and the instrument by which we can record these 
changes is called a harometer. To make this instrument a 
glass tube about 33 or 34 inches in length, and closed at 
one end, is filled with mercury, the open end closed with 
one finger and inverted into a vessel containing mercury. 
The finger should not be released until the open end is 
fully under the mercury in the vessel. The mercury in 
the tube will sink until the column is about 30 inches 
from the surface of the liquid in the vessel. The weight 
of the air pressing upon the mercury in the vessel supports 
the mercury column at the given height — 30 inches. One 
cubic inch of mercury weighs ^-pound, and if the tube were 1 
inch square the 30 inches in height would weigh 15 pounds. 
It is thus that it was ascertained that the pressure of the 
air is 15 pounds upon every square inch, for it requires a 
pressure of 15 pounds to support a column of mercury 
weighing 15 pounds. The column of mercury will rise or 
fall according to the pressure of the air; when the air is 
rare the barometer is low, when the air is condensed and 
heavy the barometer registers higher. This atmospheric 
pressure is often spoken of simply as " atmosphere ; ^^ two 
"atmospheres^^ would indicate a pressure of 30 pounds 
upon a square inch, three " atmospheres ^"^ one of 45 pounds, 
etc. The pressure decreases as the height increases, and 
increases as the distance downward from the surface of the 
earth increases. That is because as we ascend, the bulk of 
air above us becomes less, and as we descend, the bulk, and 
consequently also the weight, becomes greater. 



54 



PHARMACEUTICAL ANB MEDICAL CHEMISTBY. 



The Chomical Constituents of the Air. 

The atmosphere is a mixture of a number of gases, 
among which nitrogen and oxygen are the most abundant. 
Its composition by volume is computed to be : 



Oxygen 20.81 

Nitrogen 77.95 

Carbonic acid gas 0.04 

Aqueous vapor 1.20 



100.00 



Nitric acid. 
Ammonia. 

Sulphuretted hydrogen. 
Carburetted hydrogen. 
Sulphurous acid. 
Organic vapors. 



Traces, 



The oxygen is the animal-life-sustaining principle of the 
air, while the nitrogen dilutes it so that animals can 
thrive in it — in pure oxygen we could not live. The oxy- 
gen oxidizes the refuse matter collected by the blood, in 
the lungs, converting much of it into carbonic acid gas, 
which is exhaled, and therefore is always present in the 
atmosphere. The composition of the air going into and 
coming out of the lungs is this : 



Going into the Lungs. 

Oxygen 20.00 

Nitrogen 79.96 

Carbonic acid gas 0.04 



100.00 



Coming out of the Lungs. 

Oxygen 16.00 

Nitrogen 79.96 

Carbonic acid gas 4.04 



100.00 



It will be seen that 4 per cent, of the oxygen is converted 
into carbonic acid gas, so that air once breathed contains 
100 times more of the gas than pure air, and since the car- 
bonic acid gas is poisonous if inhaled in quantities of 4 per 
cent., it becomes apparent how essential it is to have good 
ventilation in our houses. Air as exhaled is wholly unfit 
and dangerous to breathe again. The air in houses does 
not contain carbonic acid gas from this source only — lamps 



PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 55 

and gas when burning produce a considerable quantity, a 
gas flame, for instance, as much as five or six persons. 

It would seem that the quantity of this gas in the at- 
mosphere (0.04) would gradually and constantly increase, 
but Nature, in its wise economy, provides that this gas, 
which is noxious to animal life, should serve an important 
role in the sustenance of the vegetable kingdom, in that it 
furnishes the greater bulk of the food of all plants. Plants 
draw their nourishment from two sources — from the soil, 
by absorption of moisture and mineral matter, and from 
the atmosphere, by breathing the carbonic acid gas, retain- 
ing or -fixing the carbon in their structure and exhaling 
the oxygen. The refuse of one kingdom is the essential 
life-principle of the other — animals breathe oxygen and 
produce carbonic acid gas ; the plant breathes this carbonic 
acid gas, resolves it into carbon, which it retains, and 
oxygen, which it gives out again — a beautiful natural 
reciprocity. 

The other constituents in the air are of minor impor- 
tance, and their proportion is never constant. Small pro- 
portions of nitric acid and ammonia are always present, 
while sulphurous acid and sulphuretted hydrogen are only 
found in the air of crowded cities or near manufactories, 
etc. 

Ammonia may sometimes be detected in rain water, 
which washes it out of the air, while nitric acid is usually 
found after thunderstorms. 

The latter is thought to be formed by electricity, every 
flash of lightning causing the oxygen and nitrogen in the 
air to combine with some of the watery vapor to form the 
acid. Such constituents of the air as the odorous emana- 
tions from flowers, the various bacteria, saline particles 



56 PHARMACEUTICAL AKD MEDICAL CHEMISTRT. 

from the spray of the ocean, dust, etc., are only found at 
times, and are restricted to localities. The moisture in 
the air varies much, sometimes being present in as small a 
quantity as |- per cent, or even less, while at other times as 
much as 2 per cent, is present, when the air is wholly satu- 
rated. We feel so uncomfortable on warm, close days be- 
cause the air is so saturated with aqueous vapor that the 
exhalations from our bodies (perspiration) cannot be taken 
up by it and consequently cling to our bodies. 

Carbon. 

Occurrence in Nature. — Carbon occurs in nature as coal, 
graphite, plumbago, diamond, etc. The diamond and 
graphite are crystallized forms, while all, or most all, other 
forms are amorphous. In combination it is the essential 
constituent of all organic matter; indeed, the chemical 
study of organic bodies is now termed "the chemistry of 
the carbon compounds,^^ while all organic bodies are in- 
cluded in the general term carhon compounds. Carbon is 
also a constituent of carbonic acid gas; all carbonates con- 
tain it, as well as all cyanides. AVe are familiar with car- 
bon also as lampblack, bone-black, charcoal, gas carbon, 
coke, soot, etc. AYe thus see that this element occurs in 
several forms, the three principal ones being the diamond, 
graphite and coal. 

This property of existing in two or more conditions or 
forms, which are distinct in their physical or chemical 
relations, is called allotropism, and the forms allotropic 
forms. There is no explanation for the existence of these 
conditions. AVhy the diamond occurs crystallized in octa- 
hedral (eight-sided) and other related forms in a state of 
extreme hardness, while blacklead occurs in hexagonal 



PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 57 

(six-sided) forms, with very little hardness, and lampblack 
with no hardness at all and devoid of crystalline shape, we 
are at a loss to explain. Some chemists claim that these 
allotropic forms represent the passive and active states of 
carbon. (Ozone is an active state of oxygen and distinct 
from the ordinary oxygen, which is the element in its 
passive state.) 

Properties. — Carbon in any form is insoluble, not fu- 
sible nor volatile, but combustible, forming carbon mon- 
oxide or the dioxide usually. Chemically it combines with 
many of the non-metals, but principally with hydrogen, 
with which it forms that important class of bodies known 
as hydrocarbons; with oxygen to form two oxides, CO and 
CO2, and with nitrogen in the organic kingdom. 

With hydrogen alone carbon forms hydrocarbons, but 
with hydrogen and oxygen, and the latter two in the pro- 
portion to form water, it forms carbohydrates. CH^, 
marsh gas, is a hydrocarbon. Cj^H^jO^, cane sugar, is a 
carbohydrate. The product of the combustion of carbon 
is always carbonic acid gas, CO^, at times accompanied with 
carbon monoxide, CO. 

The diamond, the most precious of the gems, is the 
purest form of carbon. Its hardness and refractory power 
are characteristic and give it its value; it is one of the 
hardest substances known, and when properly cut refracts 
and resolves white light into the primary colors like no 
other body. When heated intensely it burns, producing 
CO 2, but resists the action of any known chemical. 

Plumbago, or graphite, is an almost pure carbon, though 
most specimens contain a small proportion of iron. We 
are all familiar with this form of carbon in lead pencils, 
the graphite being erroneously called lead at times. 



58 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Lampblack is the soot produced when oil or some kinds 
of resin burn with an insufficient quantity of oxygen. It 
contains unchanged oil frequently. 

Charcoal is produced when wood is incompletely 
burned, usually by a procees known as destructive distilla- 
tion, as in the preparation of acetic acid. It may be pre- 
pared also by the smothered combustion of piles of wood 
partially covered with earth. This kind of charcoal is 
called wood charcoal, to distinguish it from animal charcoal, 
which is the residue obtained on heating bones to a red- 
heat without access of air. This residue contains, besides 
carbon, phosphate, of calcium, which when removed with 
hydrochloric acid leaves the imrified animal charcoal. 
This is a very valuable substance, because of its property of 
removing coloring matter from solutions of organic matter. 
It plays an important part in the refining of sugar. The 
crude juice from the sugar-cane yields upon evaporation a 
very dark-brown sugar, whose color is due to natural color- 
ing matter. The white granular or block sugar is the same 
devoid of the coloring matter, which is removed by filtering 
the solution of brown sugar or the crude cane-juice through 
animal charcoal contained in large percolators. 

The manufacturing chemist employs animal charcoal for 
similar purposes, and for removing certain other bodies 
from solution. Nearly all varieties of charcoal possess this 
property, but none so much as the animal charcoal. 

Charcoal prepared from dense wood has the property of 
condensing gases and vapors; it will absorb 90 volumes of 
ammonia gases, while of hydrogen it takes up about twice 
its own volume. In thus absorbing the gas the charcoal 
probably causes the gases to liquefy. 

Compounds of Carbon with Hydrogen. — Carbon and hy- 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 59 

drogen form compounds which are the starting points in 
organic chemistry. From these hydro cartons a vast 
number of compounds are derived, either by adding, taking 
away or substituting other atoms or groups of atoms; 
indeed, the complete study of the hydrocarbons, their com- 
pounds and substitution-derivatives, constitutes the entire 
science of organic chemistry. These bodies are obtained in 
nature usually by the decomposition of more complex or- 
ganic substances, but they may be made by direct combina- 
tion, in many cases, in the laboratory. Acetylene, OJS.^, 
for instance, may be obtained by directly combining the 
elements by passing a stream of hydrogen through a tube 
in which a current of electricity is passing between two 
carbon poles. 

Methane, or marsh gas, CH^, is another hydrocarbon of 
simple construction, and is produced when organic matter 
decays under water, as it does in marshes, hence the 
name. It, too, is the beginning of a long series of carbon 
compounds, and with the acetylene and ethylene or olefiant 
gas, is an important factor. 

Illuminating Gas. — The manufacture of coal or illuminat- 
ing gas is an industry of importance. The process is a 
simple one, yet in practice requires considerable skill. 
Coal is subjected to destructive distillation, which produces 
a variety of gases and other products, among which is a 
considerable quantity of ammonia, from the nitrogen which 
is always present in coal. The distillation of the coal goes 
on in large cast-iron retorts maintained at a red heat in a 
furnace. The gases and all the volatile products are con- 
ducted upward into and through a long horizontal pipe, 
containing water and called a hydraulic main. From 
there the gas passes into an apparatus which serves the 



60 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

purpose of a refrigerator, consisting of a series of vessels 
filled with water and so arranged that the gas must 
pass through a considerable quantity of water. The pro- 
cedure not only cools the gas but causes the condensation 
of tar and ammonia. Much tar is deposited in the hy- 
draulic main, from where it runs into a reservoir known as 
the tar-ivell, but the gas being still very hot not all the tar 
condenses, and some passes over, to be deposited in the 
refrigerator with the ammonia. The process of purification 
is continued by causing the stream of gas to pass through 
a chamber called the scruhber, which is filled with loose 
material, or anything that gives space. Here much sus- 
pended matter is removed. Next the gas is washed by 
being made to pass through an apparatus where it comes 
in contact with a number of sprays of water. The gas still 
contains sulphuretted hydrogen, carbonic acid gas and 
disulphide of carbon, which are removed in the purifiers. 
The latter are very large tanks filled with lime. The im- 
purities mix chemically with the lime and are retained. 
The gas is finally stored in the large gas tanks, with the 
appearance of which we are all familiar, and from which 
it is supplied to the consumer. 

Illuminating gas varies much in its composition, judging 
from its illuminating powers. If properly purified it con- 
tains methane, CH^; ethylene, CjHj acetylene, C^H^, 
hydrogen, carbon monoxide, CO; free nitrogen, a little 
disulphide of carbon and a small quantity of volatile liquid 
hydrocarbons. 

Compounds of Carbon with Hydrogen and Oxygen. — The 
carlohydrates, as already observed, are a class of com- 
pounds containing carbon ^ united with hydrogen and oxy- 
gen in the proportion to form water; there are usually six 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 61 

carbon atoms or a multiple of six present. There are 
three groups of these compounds : the glucoses, represented 
by grape sugar, fruit sugar, and all having the composi- 
tion OgHj^Og; the saccharoses, of which cane sugar, milk 
sugar and maltose are examples, having the composition 
OjjH^^Oj,, and finally the amyloses (starches), O^^fi^, 
with starch, dextrin and cellulose as representatives. It 
will be seen that the hydrogen and oxygen in each case are 
in the proportion to form water — in cane sugar, for in- 
stance the Hj^Og are equal to 6 H^O — i.e., six molecules of 
water. Cellulose, of which ordinary absorbent cotton is a 
good example, has a formula represented by a multiple of 
the six carbon atoms usually present in the carbohydrates; 
its formula is that of amylose or starch multiplied by three 
— O^gHgoOj,. The carbohydrates, like the hydrocarbons, are 
an exceedingly interesting and useful class of compounds, 
but cannot be considered here. 

Alkaloids and Glucosides. — Carbon united with hydro- 
gen and nitrogen alone, or with these and oxygen, forms 
the two series of compounds known as alkaloids and glu- 
cosides. These, too, are relegated to organic chemistry 
and cannot be dwelt upon here. 

Compounds with Oxygen. — There are two compounds of 
oxygen and carbon: CO, carbon monoxide, and CO,, car- 
bon dioxide. 

Carbok Monoxide is a combustible gas, producing 
carbon dioxide when it burns : 2C0 -|- 0, = 2CO2. I^s 
flame is a beautiful pale blue, which may be viewed in any 
coal stove when the coal has just begun to burn. The gas 
is without color, almost without odor, and is very poison- 
ous. It is produced abundantly, together with carbon 
dioxide, when charcoal burns. It rapidly produces in- 



62 PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 

sensibility and death when inhaled. When oxalic acid is 
heated with five or six times as much sulphuric acid, car- 
bon monoxide and dioxide are formed, from which mix- 
ture the dioxide may be removed by passing through a 
strong solution of caustic potassa. The dioxide unites 
with the potassa to form potassium carbonate, while the 
monoxide passes unchanged. Another method for the 
production of the monoxide is the heating of potassium 
ferrocyanide with ten times its weight of sulphuric acid. 
An abundance of the gas in a pure state is thus generated. 
Extreme care must be observed not to inhale this gas. 

Carbois' Dioxide, sometimes erroneously termed car- 
bonic acid, is always produced when anything containing 
carbon burns with a sufficient supply of oxygen. When 
the supply of oxygen is insufficient the monoxide is often 
formed. In these two gases we have a good illustration 
of the law of multiple proportions referred to in the para- 
graphs on chemical philosophy. If carbon, whose atomic 
weight is 12, combines chemically with oxygen, and there 
is only a limited supply of the latter, the combination 
takes place between 12 of the carbon and 16 of the oxygen, 
forming 28 of CO, but if the oxygen is plentiful the car- 
bon unites not with once the atomic weight of oxygen, 16, 
but with a multiple of 16 — namely, 32, producing 44 of 
CO^; that is, while the proportion of carbon is constant, 
that of oxygen increases, in the case of 00^, in a multiple 
proportion. Comhustion is ordinarily oxidation — that is, 
the union, chemically, of a body with oxygen, with the 
production of heat and flame. That body may be hydro- 
gen, sulphur or phosphorus, etc., but usually it is car- 
bon in some form or other. The burning of coal, wood, 
gas or oil is simply the union of the carbon in those bodies 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 63 

with the oxygen in the air, producing carbon dioxide. 
The blood is continually purified in our lungs by the car- 
bon in the refuse matter collected by the 'blood uniting 
with the oxygen brought into the lungs as air. 

For experimental purposes the gas is easily prepared by 
decomposing any carbonate (that of sodium is cheap) with 
an acid. On a larger scale, as in the making of the car- 
bonated waters, marble, the carbonate of calcium, is de- 
composed with acid, hydrochloric usually, or sulphuric : 

Hydrochloric Calcium Carbon 

Marble. Acid. Chloride. Water. Dioxide. 

CaC03 + 2HC1 = CaOl, -f H,0 + CO, 

Any carbonate when treated with one of the strong acids 
yields free CO,. This fact is taken advantage of in test' 
ing for carbonates. Whenever an eilervescence (evolution 
of gas) takes place when a body not a metal is treated with 
an acid, it is safe to assume that the body was a carbonate. 

Carbon dioxide is a colorless gas, with an agreeable 
pungent taste and odor. It is poisonous to animal life, as 
already observed when discoursing on the atmosphere. 
It is incombustible and does not support combustion — a 
lighted match or taper plunged into the gas is immedi- 
ately extinguished. In this respect and in others it is not 
unlike nitrogen, but may be distinguished from it by its 
rapid absorption by solution of caustic potassa or lime- 
water. The latter with the gas becomes turbid, owing 
to the formation of insoluble carbonate of calcium. The 
gas can thus be detected in the breath by blowing through 
a tube into lime-water. 

Water dissolves about its own bulk of CO,, but many 
times its volume if under pressure. Soda-water is common 
water charged with carbon dioxide under pressure. The 



64 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

soda-water can be drawn through pipes upward for a dis- 
tance, because the gas, owing to its expansive force and 
pressure, tries to get away from its confinement and carries 
the water with it. Effervescing wines and sparkling min- 
eral waters owe their effervescing qualities to carbon di- 
oxide. In the former it is produced during the process of 
fermentation, when the grape juice changes its sugar into 
alcohol; in the latter it is present through the absorption 
of the gas produced in nature, usually in the earth near 
springs. It is always a product oi fermentation diu.^ putre- 
faction. These latter terms are synonymous, in a sense 
— they both mean the decomposition of organic matter. 
When the products of the decomposition are useful the 
process is termed fermentation, as in the formation of 
alcohol by the decomposition (natural decomposition) of 
grain; but when the products are useless and offensive the 
process is called putrefaction. In many of the mineral 
waters carbon dioxide plays an important part, as has been 
mentioned in the chapter on water, to which the student 
is again referred. 

Carbonic acid gas, as the gas is often correctly termed, 
can be liquefied; it requires for the purpose a pressure of 
577 pounds to the square inch. When liquefied it is color- 
less, lighter than water and, when unconfined, four times 
more expansive than air. Because of this and its power 
to extinguish fire it may be found in many places kept in 
strong glass flasks hermetically sealed, to be used in case of 
fire. The flask breaks when thrown into a burning mass; 
the liquid at once volatilizes, extinguishing all flame it comes 
in contact with. Care must be taken that no persons or 
animals are near. 

The Carbonates form a very large and important 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 65 

series of salts, many of which occur abundantly in nature. 
Carbonate of calcium is found in nature in many forms, 
most largely as marble, limestone and chalk. The shells 
of all crustaceous animals, such as oysters, clams, lobsters, 
etc., are wholly composed of calcium carbonate. The car- 
bonate of magnesium also occurs very abundantly. The 
carbonates may be represented as containing the oxide of 
a metal united with CO2. Chalk, for instance, CaCOg, is 
CaO, oxide of calcium, and CO^ ; carbonate of magnesium, 
MgCOg, is the oxide, MgO, and CO,; white lead, PbCO^, 
is the oxide of lead, PbO, and CO,. 

Carbokic Acid, H^COg, may be looked upon as water, 
H^O, and CO,. The compound is not stable and always 
resolves itself into water and CO,. Attention should here 
be called to an error which is too often made. CO, is car- 
hon dioxide, or carbonic acid gas, and not carlonic acid, as 
it is so frequently called. There can be no acid without 
hydrogen, and carlonic acid is CO, with water, H,0, 
which furnishes the hydrogen. 

Carbon with the Halogens. — There are a number of 
compounds of carbon and chlorine known: C,C1„ C,C1^, 
C,Clg, etc., and a similar group with iodine and bromine. 

Carbon with Nitrogen forms cyanogen, CN, which is a 
colorless gas of a pungent, peculiar odor resembling some- 
what that of hydrocyanic acid. Cyanogen unites with 
hydrogen to form the most poisonous compound there is, 
hydrocyanic acid, sometimes called prussic acid. With 
metals it forms compounds called cyanides. Cyanogen is 
a good illustration of what is meant by a compound radical ; 
it is a group of elements, carbon and nitrogen, which com- 
bines with elementary bodies, and is capable of passing 
from one state of combination to another just as though 



6Q PHAKMACEUTICAL AND MEDICAL CHEMISTRY. 

it were a single element. Ammonium, NH^, is analogous to 
cyanogen in this respect, except that it acts as a base 
or like the metals, while cyanogen is related to the non- 
metals in the same sense. 

Carbon with Sulphur forms, like carbon and oxygen, two 
compounds, the monosulphide, OS, and the disulphide, 
OSj. The disulphide is of some importance in that it is a 
good solvent for some bodies which are ordinarily insolu- 
ble. It has a very offensive, repulsive odor as found in 
the market, but when pure is almost odorless. Sulphur 
is easily dissolved by it, and is again deposited in crystals 
upon evaporation of the disulphide. Its use is mostly in 
the arts, though to some extent it is utilized in extracting 
oil from seeds. It dissolves or extracts the oil, leaving it 
again upon evaporation or distillation. 

The Halogens. 

The four elements known as the halogens (salt pro- 
ducers, so called because they exist in sea-water) are chlo- 
rine, bromine, iodine and fluorine. We will consider them 
in the order named and begin with 

Chlorine. 

Chlorine is one of the natural group of elements called 
halogens, which not only have a common source, but re- 
semble each other in a marked degree in all their chemical 
relations. The similarity in chemical behavior is especially 
noticeable between chlorine, bromine, and iodine; fluorine, 
because chemists have not been able to isolate it in any 
quantities large enough to experiment with, has not been so 
thoroughly studied, but its behavior in combination is very 
like that of the other halogens in many respects. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 67 

Occurrence in Nature. — The halogens occur chiefly in 
the sea, usually in combination with sodium, potassium, 
magnesium and calcium. Chlorine is the most abundant, 
and is found mainly as the chloride of sodium — common 
salt — in the ocean, as brines, and in mines as solid crystal- 
line masses. Some springs contain it; the St. Catherine's 
water contains it in combination with magnesium. As the 
chloride of sodium it is universally distributed in minute 
quantities; the tissues of plants and animals contain it as 
an essential constituent. 

History. — The Swedish chemist, Scheele, who also dis- 
covered oxygen, discovered chlorine. While experiment- 
ing with hydrochloric acid he brought it while hot in 
contact with hraunstein, brownstone, dioxide of manga- 
nese, when he noted an irritating, suffocating gas coming 
off, which he and others subsequently proved to be an ele- 
ment; this also was in 1774. It is a peculiar coincidence 
that oxygen should have been discovered at about the same 
time by two men, Priestley and Scheele, distant from one 
another and without knowledge of each other, but it is 
more so that one body — dioxide of manganese — should 
have served in the discovery of two elements, for Scheele 
not only discovered oxygen by heating the dioxide, when 
oxygen was evolved, but chlorine as well by treating the 
dioxide with hydrochloric acid. In the first instance the 
element, oxygen, was a constituent of that from which it 
came, MnO^ , but in the case of chlorine the dioxide was 
only an agent for the liberation of chlorine from hydro- 
chloric acid, and did not furnish the chlorine itself. 

Preparation. — The accidental method which furnished 
Scheele's chlorine is to-day yet employed as the simplest, 
though there are many others. Manganese dioxide, MnO^, 



68 PHARMACEUTICAL Ai^D MEDICAL CHEMISTRY. 

is introduced into a flask provided with a safety-tube for 
pouring in the acid and a bent tube for conveying the gas 
to a receiver. A small portion of hydrochloric acid is 
poured through the safety-funnel tube into the flask and 
thoroughly shaken, so that all of the manganese becomes 
wetted; then more acid is added and gentle heat applied, 
when the evolution of the gas ensues at once, and may be 
collected as is any other gas. The equation illustrative of 
this reaction is: 

MnO, + 4HC1 = MnCl, -f 2H,0 + CI, 

Dioxide of Hydrochloric Chloride of Water. Chlorine, 

manganese. acid. manganese. 

Instead of using hydrochloric acid, sulphuric acid and 
common salt are sometimes employed — i.e., the dioxide is 
mixed with common salt, to which mixture the sulphuric 
acid is added. The common salt and sulphuric acid react 
upon each other, producing hydrochloric acid : 2 NaOl + 
H^SO, = Na.SO, + 2 HCl. The HCl thus produced in 
the operation is then acted upon by the manganese dioxide 
with the result above illustrated. 

Chlorine gas, thus produced and passed into water, con- 
stitutes the aqua chlori of the pharmacopoeia, which con- 
tains 0.4 per cent, of gas. It does not keep well, produc- 
ing hydrochloric acid through the decomposition of the 
water by the union of the chlorine with its hydrogen. 
Keeping in dark places prevents this change to an extent, 
but the water is never reliable if kept for any length of time. 

Properties. — In chemical energy chlorine surpasses many 
of the elements, even oxygen in some cases. It has a 
greenish color which is characteristic, a peculiar suffocating 
odor, and when inhaled produces distressing irritation of 



PHARMACEUTICAL Ai^D MEDICAL CHEMISTRY. 69 

the mucous membranes of the throat and lungs. Some 
claim that if respired in very minute quantities it is bene- 
ficial in pulmonary troubles. A pressure of four atmo- 
spheres liquefies the gas to a transparent yellow liquid which 
it is difficult to freeze into solid condition. That chlorine 
maintains combustion may be shown by dropping pow- 
dered antimony, arsenic or phosphorus into it; the chlo- 
rides of these will be formed almost immediately, with the 
production of heat and fiame. Burning is ordinarily oxi- 
dation ; in this case it is clilorination. An interesting ex- 
periment may be made by saturating a piece of paper with 
oil of turpentine and plunging it carefully and dexterously 
into a vesssel containing chlorine. A dense black smoke 
is emitted which usually turns into a flame from the rapid 
decomposition of the turpentine. 

The atomic weight of chlorine is 35.4, its density the 
same, and its specific gravity compared to air 2.45. It 
has but little attraction for oxygen, but all the more for 
hydrogen and the metals, with which it forms chlorides. 
Wood or wax will burn in chlorine with a dull red flame, 
burning the hydrogen only, producing hydrochloric acid. 
The bleaching power of chlorine is its most characteristic 
property; organic coloring principles which resist the 
bleaching action of other bodies are almost instantly de- 
stroyed by it. Indigo, which will not change its color 
with strong sulphuric acid, has its color discharged by 
chlorine. Whenever chlorine bleaches it does so not by 
hiding, so to say, the color, as sulphur dioxide does, but 
by completely destroying it, so that it cannot be restored. 
Water must be present for chlorine to act as a bleach- 
ing agent, as the gas in a perfectly dry condition is 
devoid of any bleaching qualities; it will not even affect 



70 PHARMACEUTICAL Ai^D MEDICAL CHEMISTRY. 

litmus when dry. In pharmacy and in the arts and indus- 
tries chlorine is used largely in the form of Ueacliing- 
foivder, which contains 35 per cent, of available gas. It is 
employed principally for bleaching cotton and linen goods. 
Chlorine is one of the most thorough and potent disinfect- 
ants, and for this purpose is usually employed to form 
the bleaching-powder, or chloride of lime, as it is errone- 
ously termed — chlorinated lime is the proper term. When 
chlorinated line is mixed with water in a flat vessel it decom- 
poses slowly through the action of the carbonic acid gas in 
the air, setting the chlorine free. Mixing a little hydro- 
chloric acid with it serves to disengage the gas more rapidly. 
It is not prudent to use the gas for disinfecting purposes, 
its use by inexperienced persons being fraught with danger. 

Compounds Containing Chlorine. — With oxygen chlorine 
cannot be united directly, all the known combinations be- 
ing produced indirectly. All the oxides and correspond- 
ing acids decompose very easily, sometimes with violent 
explosion, for which reason many of their compounds are 
employed in making explosives. The oxides and acids ob- 
tained from them by their union with water are the fol- 
lowing : 

Cl^O, Jit/pochlorotis oxide, + H^O = 2HC10, Jiypochlor- 
ous acid. 

CI2O3, chlorous oxide, -\- Kfi = 2IIC102,- chlorous acid. 

ClgO^, tetroxide. Acid not known. 

CljO^, chlorzc oxide, + ^fi = 2HCIO3, chloric acid. 

Cl^O,, ^;erchlor2c oxide, -f H„0 — 2HC10^, jjerchloric 
acid. 

In viewing the composition of these oxides it will be 
seen that the quantity of chlorine is constant in each, the 
quantity of oxygen increasing, which illustrates again the 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 71 

law of multiple proportions. It not only illustrates this 
law, it teaches also 

A Lesson in Nomenclature^ 

i.e., the naming of compounds. Here we have a series of 
combinations, all containing the two elements, but each 
containing one element in different proportion from that 
in another. Now, it is this difference, in the quantity of 
oxygen in this case, that enables chemists to apply a defi- 
nite specific name to each combination. The terms mono, 
di, tri, tetra and pentoxide would be names for combina- 
tions containing, respectively, one, two, three, four and 
five atoms of oxygen. Besides these numerical terms the 
chemist employs others which are relative ones, the rela- 
tion starting from some one combination. These relative 
terms are the true chemical names. To the highest form 
of oxidation is usually given a name, to which the names 
of the others bear a relation. In this case the Cl^O^ was 
once thought to be the highest form of oxidation of chlo- 
rine, and was called chlor^c oxide, the ic always meaning 
higJiest, The Cl^Og was the next highest, or the one next 
below the highest, and it was termed chloro?^s oxide, the 
o^cs meaning loiver. There being also a Cl^O, that is, with 
the Cl^Oj, two chloro2^s oxides, another prefix had to be 
employed to show that the 01^0 was a combination of the 
ous kind, though lower than one already called chlorous. 
The prefix hypo was called into requisition, which means 
heneath, so that the hypoohlovous oxide 01^0 is a combina- 
tion lower than the chloroz^s oxide. For the CI2O, a name 
had to be chosen which would indicate that it was a 
union of chlorine and oxygen with even more oxygen in 



72 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

it than the one termed chloric oxide. The prefix per 
means above, so that the word pe^^oxide means above the 
highest oxide. (Intrinsically the Cl^O, would be the chloric 
oxide, etc.) What has been said of the names of the com- 
binations of oxygen and chlorine is not confined to these, 
but the principles are qenerally ajjplicahle in chemical 
nomenclature. 

With hydrogen, and with hydrogen and oxygen, chlorine 
forms acids, which may be directly derived from the above 
oxides by adding water, except in the case of hydrochloric 
acid, as can be seen above. Most oxides of the non-metals 
form acids with water, the hydrogen in the water forming 
the base of the acid, and without which no acid can exist. 

It will be seen that with loater the various non-metallic 
oxides form acids which have the same names as the oxides. 
Knowing, therefore, the name of an oxide, we can tell the 
name of its corresponding acid, and vice versa. The cor- 
i^esponding acid of an oxide is what is obtained when 
water is added to that acid; for instance, the acid corres- 
ponding to the chlorous oxide, Cl^Og, is chlorous acid : 



01,03 + H,0 = 2H010 



The names of the acids furnish us names for the salts 
which are formed from the acids. Salts are generally 
derived by replacing the hydrogen in acids by a metal. 
Thus, if we replace the H in hydrochloric acid, HOI, 
with sodium, Na, we get NaOl, which is a salt; so by 
putting an atom of magnesium, Mg, in place of the H in 
sulphuric acid, H.SO,, we get MgSO,, also a salt. Let 
us now make salts from all of the chlorine acids. The 
only acid not containing oxygen in this series is hydro- 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 73 

chloric acid, which can be made by direct union of H 
and 01. 

If in the following acids the The following-named salts will be 

hydrogen is replaced by produced : 

sodium, 

Hydrochloric acid, HCl. . . | ^^^M^^f '''^''''^' ""' '''^''' \ ^^^^ 

Hypochlorous " HCIO. j ^^g^^?!;^^^^ 

Chlorous - HCIO. ] ™MonYf! '^^'""':.^^^ 

Chloric " HClOa ] ^'^chlom?/ ^''^''''^' ""' ^''^''' \ ^^^^^' 

T>^««ui^«i^ (f rrmrk \ Pcrchlortt^e of sodlum, or } ^^ ^.„^ 

Perchloric HCIO. -j god ic perchlora^.. .......[ ^^^^^^ 

It will be seen from this that acids having the prefix hydro 
and the suffix ic make salts ending in ide : hydrochloric 
acid yields a chlor^V?e of any metal. The acid whose name 
ends in ous and has hypo for prefix yields salts called hypo- 
chloTites; the ous acids yield ite salts : chlorous acid gives 
chlor^^e of a metal, sodium, in this illustration; the ic acids 
yield salts whose names end in ate : chloric acid yields 
chlovates; acids having names with per for prefix and ic 
for suffix yield salts whose names begin with per and end 
in ate : perchloric acid yields ^erchlora^e^, it being under- 
stood that in each case the hydrogen of the acid is replaced 
by a metal. 

Experiments. — Before beginning the discourse upon the 
uses of chlorine in pharmacy, directly and indirectly, its 
importance warrants the giving of a little time to experi- 
menting, especially with a view of illustrating more fully 
its properties, chemical and physical. Besides those given 
before, the following experiments may be made by the 
student. He is advised to experiment whenever practica- 
ble, and to record his observations for future reference, 
and always to be careful in his experiments. 



t4 PHAEMACEUTICAL AND MEDICAL CHEMISTKY. 

1. Illustrating Diffusion of Gases. — If chlorine gas 
be made, as before directed, by displacing water in a flask 
and the flask exposed to the atmosphere, it will take a long 
time for the green color of the gas to disappear; the dis- 
appearance of the color naturally indicates the disappear- 
ance of the gas. If another flask containing chlorine gas 
be inverted, the flasks being in both instances without 
stoppers, it will require only a very short time for the 
chlorine to mix with the atmosphere and the flask to 
become fllled with air. 

This phenomenon is due to the fact that chlorine is 2.5 
times heavier than air. If it were not for a natural law, 
the laio of diffusion of gases, the chlorine in the first flask 
would remain there indefinitely, being much heavier than 
air, for it must be remembered that gases, like liquids, 
when carefully mixed, arrange themselves in layers accord- 
ing to their densities. The layers of liquids (in case of 
miscible liquids) when once arranged remain so perma- 
nently; for instance, a test-tube containing sulphuric acid 
may have a layer of water poured in without disturb- 
ing the sulphuric acid — i.e., the acid and water form 
two layers which remain permanent if not disturbed by 
some external force. The same is true of gases, so far as 
their arrangement according to their density or heaviness 
is concerned, at first, but the layers are not permanent. 
Notwithstanding the different densities of gases, they will 
diffuse or intermingle with each other in admixture until 
the mixture will have attained a mean density. Where 
there is no limit by a containing vessel, as in the atmo- 
sphere, the diffusion practically goes on indefinitely. (See 
physical properties of hydrogen on pages 29 and 30.) 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 75 

2. Illustratiitg Bleaching Properties. — Make chlo- 
rine gas as before, and pass it through a tube or bottle con- 
taining chloride of calcium, and conduct it to the bottom 
of the bottle which is to contain it. The bottle will be- 
come filled with chlorine, which disi^laces the air. The 
object of passing the gas through the calcium salt is to 
remove any watery vapors with which it may be mixed, to 
obtain a thoroughly ^r?/.gas. The chloride of calcium has 
a great affinity for water, and absorb sit from its mixture 
with a gas. A piece of dry litmus-paper or a dry red rose 
plunged into this dry chlorine gas will not have its color 
affected. Moisten the litmus-paper or the rose, and again 
introduce into the chlorine. The color begins to dis- 
charge, and very soon the paper or rose will be perfectly 
white. This illustrates that chlorine will not bleach unless 
water is present. 

A little chlorine -water poured into ink or red wine or 
indigo solution causes each of the liquids to lose its color. 
All colors derived either from the animal or vegetable king- 
dom are lileaclied or destroyed hy chlorine. This property 
makes chlorine a most important agent for bleaching 
cotton, linen, paper and many other materials. It renders 
these bodies perfectly white in a few hours, while the old 
method of bleaching by laying the goods on the grass in 
sunshine required weeks, and sometimes months. 

3. Illustrating Disinfecting and Deodorizing 
Properties. — If chlorine-water is applied to decaying and 
badly smelling substances (stagnant water, rotten eggs, 
etc.) the bad odor vanishes very quickly. 

It not only decomposes colors, but also the products 
formed during decay, and which produce nauseous odors. 
Morbific matter, disease germs, miasms, which, by being 



76 PHARMACEUTICAL Ai^D MEDICAL CHEMISTRY. 

diffused in the air or attached to beds, clothes or walls 
may communicate disease, are acted upon in a similar 
manner. Chlorine is therefore a deodorizer and powerful 
disinfectant, purifying infected atmospheres and all kinds 
of morbid matter, and arresting or checking the decay of 
organic substances. 

4. Illustrating- the Affin"ity of Chloriis^e for 
Htdrogek. — Fill a small flask with chlorine-water and 
invert into a vessel containing water, and put away into the 
dark; there will be no change and the chlorine water will 
keep for a tolerable length of time; but if the flask be ex- 
posed to sunlight decomposition will soon ensue, with the 
formation of a gas which collects in the upper part of the 
flask. After a few days the water will have lost all of its 
chlorine odor and will have acquired a sour taste, and in- 
stead of bleaching litmus paper will turn it red, showing 
acid reaction. The gas collected in the upper part of the 
flask will be found to inflame a glowing taper and exhibit 
other properties which establish its identity as oxygen; the 
acid reaction is due to the presence of hydrochloric acid. 
We began with chlorine and the elements of water, hy- 
drogen and oxygen. These, later on, are yet present, but 
not in the original condition or combination — the chlorine 
being now not free or uncombined, as it at first was, but 
in combination with the hydrogen as hydrochloric acid. 
In other words, chlorine has much chemical affinity, so 
much, in this case, that it decomposes water, under the in- 
fluence of sunlight, and unites with the hydrogen, setting 
free the oxygen, thus: 2C1, + 2H,0 = 4HC1 + 0,. When 
the water is decomposed the chlorine has the choice of 
uniting with oxygen or with hydrogen, but it selects the 
latter, affording an example of what is termed 8imi:)le elec- 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 77 

tive affinity. Now, this very chemical affinity of chlorine 
for hydrogen explains its bleaching and disinfecting power. 
When chlorine bleaches it simply causes the decomposition 
of the coloring matter in order to unite with the hydrogen 
which is present in all animal and vegetable bodies. By 
this abstraction of the hydrogen a rearrangement of mole- 
cules to form other combinations is necessary, causing the 
coloring matter to become colorless. 

5. Illustrating the Affinity of Chlorine for 
Bases. — Make a solution of iodide of potassium or of the 
iodide of any base, and add freshly-made chlorine-water; 
the iodine will be set free and the chlorine take its place, 
making a chloride of potassium. 

Treat a solution of any bromide with culorine-water or 
any form of free chlorine — the bromine becomes liberated 
and may be recognized by its odor and color. This shows 
the chlorine to have more affinity for the base than the 
bromine or iodine has, which it replaces in all their 
combinations. 

6. Showing the Solvent Power, Chemically, of 
Chlorine. — Into chlorine-water put a leaf of pure gold; 
it will disappear in a short time, uniting with the chlorine 
to form chloride of gold. It is the only substance that 
will dissolve gold (nitro-hydrochloric acid dissolves gold, 
but it does so because it probably contains free chlorine). 
Chlorine combines thus with many of the metals, forming 
chlorides of the respective metals, as has already been re- 
ferred to in case of antimony and arsenic. Copper in the 
form of wire or sheet burns in chlorine gas, forming a 
solution of copper chloride. If into this latter solution a 
piece of bright iron or steel is placed it very soon becomes 
covered with a red coating of copper. In chemical reac- 



78 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

tions the right of the strongest prevails, and the chlo- 
rine, possessing stronger affinity for iron than for copper, 
seizes the iron, forming a chloride of iron, and liberates 
copper, which is deposited in the metallic condition. 
Polished steel is, therefore, a reagent for copper and may 
be employed to ascertain the presence of copper very 
simply and quickly. Copper is sometimes detected in this 
way if present in pickled cucumbers or preserved fruit, to 
which it is sometimes added to give a fresh-green color. 

7. Showixg the Test of Iden"tity of Chlorixe iif 
CoMBiXATiOK" AS Chloride. — To a solution of any chlo- 
ride add solution of silver nitrate — a heavy white precipi- 
tate will be formed which is insoluble in nitric acid, but 
quickly soluble in ammonia-water. 

Chlorates when heated evolve oxygen, the residue 
being chlorides. 

Chlorine in Pharmacy. — Aqua chlori, U. S. P. has been 
already incidentally considered. 

Calx Chlorata. — This is a compound resulting from the 
action of chlorine upon calcium hydroxide (slaked lime), 
and containing at least 35 per cent, of available chlorine. 
It is erroneously called chloride of lime — properly it should 
be termed clilorinated lime. Calcium hydroxide, Ca(0H)2, 
placed in trays in suitable chambers, is exposed to the 
action of chlorine, which is absorbed by the lime, forming 
a compound having the formula CaCl2Ca(C10)2. Its 
formula is sometimes written CaOCl, (the former divided 
by two), which gave rise to the name Ghloiide of lime, 
the CaO being the formula for lime and the Cl^ de- 
noting chloride. In correct chemical nomenclature we 
cannot recognize the latter name. It is proper, though, to 
speak of the compound as cliloY'mated lime, the hydroxide 



PHARMACEUTICAL A^B MEDICAL CHEMISTRY. 79 

being made from lime, CaO, by adding water or slaking it: 
CaO + H,0 = Ca(OH), 

Chlorinated lime is valuable chiefly for the chlorine it 
contains, and which is easily available, being very loosely 
combined. It is used largely as a disinfectant through its 
power of arresting decay and putrefaction. Sometimes, 
though rarely, it is used internally. Its chief use in phar- 
macy is to make the solution of chlorinated soda of the 
Pharmacopoeia, or Labarraque's Solution. 

The manufacture and introduction into the market of 
chlorinated lime, or bleaching -poivder, as it is frequently, 
termed, was brought about by manufacturers being pro- 
hibited from allowing the chlorine which was a by-prod- 
uct in many processes of manufacture, to escape into the 
air. .Air containing chlorine is not fit for breathing, nor 
is water containing chlorine fit for fishes to live in, as the 
manufacturers soon learned when they tried to dispose of 
their waste chlorine by conducting it into the rivers. At 
a loss what to do with it, they began experimenting, and 
soon a chemist suggested passing it into lime. His sug- 
gestion was adopted readily, but it was not thought that 
this apparently useless product would soon be in such 
demand that more than waste chlorine would be necessary 
to make enough to supply the need for it. Exposed to the 
air it emits chlorine spontaneously; if it is desired to have 
the chlorine evolved rapidly, a little hydrochloric acid 
added will hasten the disengagement of the gas. 

Bleaching-powder should be preserved in well-closed 
vessels and kept in dry places. 

Liquor Sodse Chloratae. — The solution of chlorinated 
soda is another convenient form for the use of chlorine. 



80 PHARMACEUTICAL AND MEDICAL CHEMISTEY. 

It is made by adding solution of common washing-soda, 
sodium carbonate, to solution of bleaching-powder. The 
calcium is replaced by sodium : 



Calcium 


Sodium 


Calcium 


Sodium 


ypochlorite. 


Carbonate. 


carbonate 


hypochlorite 


Oa(ClO), 


+ Na.CO, : 


= CaC03 


+ 2]S[a010 



The calcium carbonate is insoluble and settles to the 
bottom, when the clear soda solution can be poured off. 

If potassium carbonate is employed in place of the 
sodium salt a corresponding potassium hypochlorite will 
be formed, the solution of which is known as Javelle's 
water. The values of both these solutions are equal. 

Hydrochloric and other acids containing chlorine will be 
referred to in the chapters on acids. 

Iodine. 

Occurrence in Nature. — Like other halogens, iodine oc- 
curs in nature chiefly combined with sodium and potas- 
sium; combinations with other bases are sometimes found. 
It chiefly occurs in the sea-water, but certain springs 
furnish it in large proportion. 

Source. — Many marine plants have the power of absorb- 
ing or abstracting the combinations of iodine from sea- 
water and storing them in their tissues, and this source — 
marine plants — furnishes all of the iodine in commerce. 

Preparation. — To obtain the iodine from the plants, the 
latter are burned, and the ashes, which are known as help, 
are lixiviated — that is, water is passed through them, as 
the menstruum is passed through the drug in the process 



PHARMACEUTICAL AI^D MEDICAL CHEMISTRY. 81 

of percolation. The solution thus obtained is filtered and 
concentrated by evaporation, allowing it to cool at times, 
to permit the other less soluble salts to crystallize. The 
chloride and carbonate of sodium and the chloride of 
potassium — all salts found besides the iodides in the ashes 
of sea-plants — crystallize out in the order named, leaving 
the iodides, because most soluble, to remain until last in 
solution. 

The dark-brown liquid which is left, called the mother' 
liquor (a mother-liquor is that liquid which is left, in any 
process of crystallization, after one or more crops of crys- 
tals have been separated), and which contains the iodine 
almost wholly as iodide of sodium, with some iodide of 
magnesium, is treated in a manner exactly analogous to 
that employed in making chlorine, viz. : it is treated with 
sulphuric acid and dioxide of manganese and gently heated 
in a retort, usually a leaden one, when the iodine distils^ or 
better, sublimes over, and is condensed and collected in a 
receiver. Theoretically the operation is similar to that 
for obtaining chlorine in one case. 

2]SraI -f 2H,S0, -f MnO, == 

2B.fi + Na,SO, + MnSO, + I,. 

In this and many other chemical respects iodine closely 
resembles chlorine and the other halogens. 

Of late years considerable iodine has been obtained in 
Chili from the mother-liquors obtained from the crystalli- 
zation of nitrate of sodium, which is abundant there as an 
efflorescence on the soil. 

Purification. — The iodine as thus obtained is in very 
impure condition, the main impurities being iodide of 



83 PHARMACEUTICAL A^D MEDICAL CHEMISTRY. 

cyanogen, or cyanide of iodine as it is frequently termed, 
chloride of iodine and water. To remove these, resuUima- 
tion is resorted to. The crude iodine is first very gently 
heated in proper vessels to allow the more volatile chloride 
and cyanide to escape; increased heat then sublimes the 
iodine; water is removed by bringing in close proximity 
with freshly-burned lime ; the lime abstracts the water : 
CaO + H,0 = Ca(OH),. 

Detection of Impurities. — When the iodine adheres to 
the interior of the bottle it does so because of the presence 
of water. Sometimes as much as 10 or 15 per cent of 
water is present, but its presence is injurious only in so 
much that it renders preparations made from it weaker 
than they should be. If iodine containing water is shaken 
with chloroform it does not give a clear and limpid solu- 
tion, but a milky onC, from which the water will separate 
if allowed to stand for some time. 

Chloride of iodine, if present, gives to water shaken with 
the iodine a brownish color, a deep brown one if much is 
present. To detect the cyanide the pharmacopoeia directs : 
If the iodine be removed from a dilute aqueous solution 
by agitation with disulphide of carbon, and, after the 
separation of the latter, some dilute solution of ferrous sul- 
phate, with a trace of ferric chloride, be added, and finally 
solution of soda, and the v\^hole supersaturated with hydro- 
chloric acid, no blue precipitate should make its appear- 
ance. 

Properties. — Iodine is in form of crystalline scales of a 
bluish-black color and metallic lustre. It is nearly five 
times as heavy as water, in which it is only very sparingly 
soluble; soluble in alcohol, ether, chloroform and disul- 
phide of carbon. At ordinary temperatures it volatilizes 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 83 

slowly; when heated it melts and rises as purple vapors, 
which are the heaviest aeriform vapors known. Applied 
to the skin iodine imparts a deep brown stain, which 
may be removed with ammonia-water. 

Iodine precipitates most of the alkaloids, forming insol- 
uble compounds with them. In chemical behavior iodine 
resembles chlorine, but its chemical behavior is weaker. 
Its symbol is I; its atomic weight, 126.85. 

Compounds. — Iodine combines with many of the non- 
metallic elements and with most of the metals, forming 
iodides and iodates. With oxygen it forms principally the 
I3O5 and three acids — the iodous, iodic and periodic. 

Of the iodides, those of potassium and sodium are most 
important in pharmacy, with the ammonium and iron 
following. The hydrogen iodide, hydriodic acid, and the 
iodides of mercury, too, are largely used. The iodine in 
these is loosely combined, wherefore the salts should be 
kept in well-stoppered bottles, away from sunlight and in 
a cool place. 

Pharmaceutical Preparations. — The Tincture of Iodine 
is probably the most largely used preparation of iodine. 
It is made by dissolving 70 grammes of iodine in enough 
alcohol to make 100 cc, and should be made frequently 
and in small quantity, as the iodine reacts with the alcohol, 
especially when exposed to sunlight. It is used mainly 
externally, though at times it is given internally. Water 
decomposes the tincture, with a separation of the iodine. 
Next to the tincture in importance is the Compound 
Solution of Iodine, or Lugors solution, which differs 
from the tincture in being a solution of iodine in a 
solution of iodide of potassium. Iodine alone is not 
soluble in water, but in the presence of iodide of potas- 



84 PHAKMACEUTICAL AND MEDICAL CHEMISTRY. 

sium it becomes readily soluble, and an aqueous solution 
is tbus possible. Five parts of iodine and 10 parts of 
iodide potassium will dissolve in 85 parts of water. 

This solution is intended mainly for internal adminis- 
tration, and its medicinal value depends not upon the 
iodide of potassium but upon the iodine, and the dose 
should be regulated according to it. There is no chemical 
reaction between the iodine and potassium iodide, the 
latter acting simply as a mechanical solvent. 

The preparation of the Ointment of Iodine depends 
upon the same fact. Four parts of iodine are rubbed with 
one part of potassium iodide and two parts of water, 
and, finally, with enough benzoinated lard to make 100 
parts. The object of the water and potassium iodide is 
to bring the iodine into a state in which it may be thor- 
oughly and equally incorporated with the lard. Alcohol 
was formerly used to effect solution of the iodine, but the 
present method has been found to be a better one. A 
little glycerin obviates the formation of crystals in the 
ointment, which sometimes happens. If kept for a length 
of time this ointment undergoes change, hence it should 
be prepared when wanted for use. It is used whenever 
iodine is indicated and the ointment is the more con- 
venient form of administration. 

Iodized Starch is obtained by triturating starch and 
iodine with a little water and drying. It is used inter- 
nally, but is not of much importance. 

Tests For Iodine and Iodides. — Free iodine gives a 
characteristic deep blue color with starch-paste. The 
latter is made by toiling a small quantity of starch with 
water. 

Chlorine having more affinity for bases than iodine, the 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 85 

latter can be liberated from iodides by treating their solu- 
tion with chlorine-water. 

Strong sulphuric acid dropped on any dry iodide also 
causes the iodine to be set free. 

Any iodide gives, with a solution of silver nitrate, a 
yellowish-white precipitate, which is insoluble in nitric 
acid and but slightly soluble in ammonia-water. (Chlo- 
rides give a white precipitate, readily soluble in ammonia.) 
Mercuric chloride, or any soluble mercuric salt, gives, with 
an iodide, a red precipitate of mercuric iodide. 

Any soluble lead salt produces a yellow precipitate with 
an iodide. 

Bromine. 

Occurrence in Nature. — Bromine, the third of the halo- 
gens, occurs in the sea and saline springs principally as 
bromide of calcium, sodium and magnesium. 

Preparation. — It is chiefly obtained from bittern, the 
mother-liquor, obtained by evaporating hrine from salt- 
wells. The mother-liquor containing the bromine, chiefly 
as magnesium bromide, is treated with chlorine, which, how- 
ever, having greater chemical affinity for the bases, com- 
bines with magnesium, in this case, setting the bromine 
free. (It must be remembered that chlorine has the great- 
est affinity of the halogens.) The bromine is condensed 
and collected in cooled receivers under water. This equa- 
tion expresses the reaction : MgBr^ + 01^ = MgCl^ -f Br^. 

Properties. — Bromine is the only liquid non-metallic 
element. At ordinary temperatures it is a dark-brownish 
red, mobile liquid, giving off brown fumes of an exceed- 
ingly offensive and suffocating odor; it is very volatile 

\ 



86 PHARMACEUTICAL AlTD MEDICAL CHEMISTRY. 

and must be kept under water, in which it is not very 
soluble. It is freely soluble in ether, carbon disulphide 
and alcohol, and has a specific gravity of 2.99. Symbol, 
Br; atomic weight, 80. Great care should be exercised in 
handling bromine. 

Compounds. — Of the compounds containing bromine, the 
bromides of potassium, sodium, ammonium and hydrogen 
are the most largely used. They will all be considered 
under the respective bases. 

■Tests for Bromine and Bromides. — Chlorine-water 
will liberate bromine from its combinations. Its odor is 
very characteristic. With starch it gives a yellowish color 
(iodine gives blue). Bromides, like iodides, give with silver 
nitrate a yellowish-white precipitate, insoluble in nitric 
acid and sparingly in ammonia-water. Strong sulphuric 
acid added to any dry bromide liberates vapors of bromine. 

Fluorine. 

This element is of little or no importance in medicine 
and pharmacy. It occurs chiefly as fluorspar (calcium 
fluoride). In its elementary state fluorine is scarcely 
known, because it so quickly and fiercely combines with all 
kinds of substances that chemists have had great difficulty 
in obtaining it in a free condition. Hydrofluoric acid 
attacks glass with such force that it is largely employed in 
the arts for etching on glass. 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 87 

Sulphur. 

Occurrence in Nature. — In Sicily and other parts of the 
world sulphur is found in the free or uncombined state, 
while as sulphides and sulphates it is very widely diffused, 
In its free condition it is found in the neighborhood of 
volcanoes, usually in opaque, crystalline masses, but some- 
times in beautiful transparent yellow crystals. It is found 
as sulphides in combination with iron, copper, lead and 
mercury; as sulphates with calcium, barium, magnesium. 

Preparation. — The crude sidphur is simply heated until 
it volatilizes, and the vapors cooled — that is, it is suhlimedy 
which in a measure purifies it. Iron pyrites or iron sul- 
phides yield a large quantity of sulphur when heated or 
sublimed. 

Properties. — Sulphur when pure is a pale-yellow solid, 
permanent in the air, insoluble in water, soluble in disul- 
phide of carbon, from which it may be crystallized. 

When heated, sulphur melts and distils or sublimes, 
unaltered, if air is absent ; in presence of air it takes up 
oxygen and becomes sulphur dioxide gas, SOj, just as it 
does when it burns. There are two forms of crystals of 
sulphur — an octahedral (eight-sided), in which the native 
sulphur sometimes occurs, and the monoclinic, obtained 
when a mass of sulphur is melted and, after partial cooling, 
the crust on the surface is broken and the fluid portion 
poured out. The crystals adhere to the inner portion and 
protrude into the space left by the portion which had not 
yet cooled and was poured out. The former is sometimes 
spoken of as the octahedral variety, and the latter as the 
prismatic variety. The former has a specific gravity of 
2.04, while the prismatic weighs only 1. 96 times as much as 



88 PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 

water. Sulphur melts at 218° P., and boils or volatilizes at 
752° F. It is interesting to notice that when sulphur is 
heated to the melting-point it forms a thin amber-colored 
liquid, which, when further heated, begins to thicken and 
becomes of a deeper color. At 430° or 450° F. it becomes 
very thick and tenacious, so much so that the vessel con- 
taining it may be inverted without losing its contents. If 
this now be poured into water and quickly cooled it be- 
comes a very soft and flexible solid, which gradually 
hardens and becomes brittle. This condition may be 
looked upon as an amorphous one. 

From the last-mentioned temperature up to its boiling- 
point, 752° F., sulphur again begins to become thin and 
limpid. 

Sulphur, in its chemical relation, bears some resemblance 
to oxygen; many of the oxides have corresponding sul- 
phides; for instance: 

HgO, Mercuric oxide. HgS, Mercuric sulphide. 

CaO, Calcic oxide OaS, Calcic sulphide. 

FeO, Ferrous oxide. FeS, Ferrous sulphide. 

Fe^Og, Ferric oxide. Fe^Sg, Ferric sulphide. 

PbO, Lead oxide. PbS, Lead sulphide. 

Official Sulphurs. — The pharmacopoeia recognizes the 
sublimed, washed and 2)'^ecipitated sulphur, the ointment 
and the sulphur iodide. 

Sublimed Sulphur.— Vapors of sulphur when con- 
ducted into a cooled chamber become condensed in the 
form of a crystalline powder, which deposits upon the 
bottom and walls of the chamber, constituting the variety 
of sulphur known as the sublimed. 

Flowers of Sulphur, as it is frequently called^ usually 



PHARMACEUTICAL AlTD MEDICAL CHEMISTRY. 89 

has an acid reaction, due to the absorption of oxygen and 
water, forming sulphurous and sometimes even sulphuric 
acid. This is not a very pure product; it may contain 
other impurities besides the acid, sometimes even traces 
of arsenic, especially if made from the iron pyrites. To 
insure purity the sublimed sulphur is washed with am- 
monia-water, yielding a product official under the name 
Washed Sulphur. The ammonia-water serves two pur- 
poses — it neutralizes the acid, forming sulphite and sul- 
phate of ammonium : 



Sulphuric 


Ammonia 


Water. Ammonium 


acid. 


water. 


sulphate. 


H,SO, 


+ 2NH,0H : 


= 2H,0 + (NHJ,SO., 



and dissolves out any arsenic that may be present. Sub- 
sequent washing with much pure water insures the total 
removal of the salts thus formed. The U. S. P. gives a 
test to ascertain the absence of arsenic. If the sulphur 
is digested with ammonia-water and filtered, the filtrate, 
if arsenic is present, turns cloudy when supersaturated 
with hydrochloric acid. This depends on the fact that 
arsenic is soluble in the alkali, but insoluble in the acid. 
The cloudiness would be due, therefore, to .the precipita- 
tion in the acid solution of the arsenous sulphide. Or 
if the above filtrate be treated with sulphuretted hydrogen, 
made by acting on sulphide of iron in a test-tube with 
sulphuric acid, FeS -f H^SO, = FeSO, + H,S, no precipi- 
tate should be produced, showing the absence of arsenous 
oxide. 

This form of sulphur is preferred by some for internal 
administration. 

The Precipitated Sulphur is much lighter and more 
easily suspended in liquids, and is therefore preferable to 



90 PHARMACEUTICAL AI^D MEDICAL CHEMISTRY. 

the other forms of sulphur. It is made by boiling together 
the sublimed sulphur and lime, filtering the solution and 
adding hydrochloric acid: 



Lime. 


Sulphur. 


Bisulphide 
calcium. 


Thiosulphate 
of calcium. 


3CaO 


+ 3S, : 


= 20aS, - 


h CaS,0, 



The solution containing the above calcium salts, when 
treated with hydrochloric acid, separates the sulphur in a 

finely-divided state : 

Calcium chloride. 
2CaS, + CaS,03 + 6HC1 = 3S, + 3CaCl, + 3H,0 

The precipitate is thoroughly washed with much pure 
water. 

The test applicable to the washed sulphur may be applied 
to this form of sulphur. 

If sulphuric acid be employed in place of hydrochloric, 
the precipitated sulphur is contaminated with calcium sul- 
phate, which is formed in the operation, and which, because 
it is insoluble, cannot, like the chloride of calcium, be 

washed out: 

Precipitate. 
2CaS, + OaS,03 + 3H,S0, = 3S, -f 3CaS0, -f 3H,0. 

This kind of precipitated sulphur is known as milk or lac 
sulphur, and should not be mistaken for the official form. 

Iodide of Sulphur. — By rubbing together very thor- 
oughly washed sulphur and iodine, and heating in a flask, 
carefully at first, not to dissipate the iodine ; increasing the 
heat, when combination has taken place, to liquefaction; 
allowing to cool, breaking the flask and reducing the fused 
mass to small pieces, the iodide of sulphur is obtained. It 
is in the form of a grayish-black solid, and when exposed 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 91 

to the air gradually loses its iodine, the latter being very 
loosely combiaed with the sulphnr. Its use is chiefly ex- 
ternally, as ointment in skin diseases. 

Sulphur Ointmekt. — Made by rubbing sublimed sul- 
phur with benzoinated lard. This is a convenient form 
for the administration of sulphur when the small propor- 
tion of acid present in the sulphur is of no consequence. 

Alkaline Sulphur Ointment. — This was introduced 
into the 1880 pharmacopoeia, and is made with ivaslied 
sulphur potassium carbonate (the latter giving it its 
alkalinity, and hence its name) and benzoinated lard. 

With hydrogen sulphur forms a gas known as sulphur- 
etted hydrogen, or hydrosulphuric acid gas, which is of 
considerable importance in that it is one of the important 
reagents in pharmaceutical testing. Its composition is 
H^S, one of those combinations in which sulphur has only 
two bonds, and which are known as sidpliides, exemplified 
in the sulphide of iron, FeS; sulphide of lead, PbS, etc. 
H^S is an acid corresponding to those acids formed by the 
union of any of the halogens with hydrogen- — that is, it is 
one of those acids containing no oxygen, and which be- 
long to the hydrochloric-acid type, HOI. It may be ap- 
propriately mentioned here that in 

The Writing of Salts 

Or acids — that is, expressing their composition by means of 
symbols — among others, two types, the HCl type and the 
H^O or water type, are employed. 

For example, we may make, theoretically, a number of 
acids from hydrochloric acid by replacing its chlorine with 
some other one element: HCl, with the chlorine replaced 
by bromine, gives HBr, hydrobromic acid ; in like manner, 



92 PHARMACEUTICAL A:N"D MEDICAL CHEMISTRY. 

HI^ hydriodic acid, HFl, hydrofluoric acid, etc., may be 
obtained. It will be noticed that the elements in the above 
acids all have one bond; an element replacing another 
must have an equal number of bonds in these cases. If the 
chlorine in the hydrochloric acid should be replaced by 
sulphur it would be necessary to employ at least two mole- 
cules of the acid, because sulphur, having two bonds, would 
replace two atoms of any element having only one bond; 
2HC1 or H2CI2 with the Clj replaced by one atom of sul- 
phur would give H^S. All acids, therefore, containing 
only two kinds of atoms may be said to be derived, theo- 
retically, from one or more molecules of hydrochloric 
acid in which the chlorine is replaced by an equiv- 
alent of some other element. The hydrogen must not be 
replaced, because it forms the base of all acids, and when 
it is removed the combination is no longer an acid, as we 
shall see presently. 

The other type, the water type, differs from the former in 
having one of the hydrogen atoms in water replaced usually 
by two or more other elements, one of which must be oxygen. 
Water is H^O, or H — — H; the right-hand hydrogen is the 
one that may be replaced. Nitric acid, HNO3, may be looked 
upon as H — — H in which the one H is replaced by NO, 
thus, H — — NO^. The group of elements replacing this 
one hydrogen must have, together, one free bond; in this 
case the nitrogen has five bonds, and two atoms of oxygen 
together four bonds, which unite with four of the nitrogen, 
leaving one bond still free. NO^, therefore, is the equiva- 
lent in combining power of a single atom having one bond, 
and can replace the one atom of hydrogen in water, just as 
bromine can replace the chlorine in hydrochloric acid. 



PHARMACEUTICAL AI^D MEDICAL CHEMISTRY. 93 

Sulphuric acid, H^SO^, because it has two hydrogen 
atoms, is derived from two molecules of water: 

H— 0— H 
H— 0— H, 

in which two atoms of hydrogen, one from each molecule 
of water, are replaced by SO 2, sulphur dioxide : 

iZo/SO,, or H,SO.. 

Phosphoric acid is derived from three molecules of water, 

H— 0— H 
H— 0— H, 
H— O—H, 

in which the three atoms of hydrogen are replaced by PO : 

H— 0\ 
H— O^PO. 
H— 0/ 

In the case of sulphuric acid the S has six bonds, four 
uniting with the four of the two atoms of oxygen and the 
other two replacing the two hydrogens. Together, there- 
fore, SO, has two free bonds. For a similar reason PO has 
three bonds, two of the five which phosphorus has uniting 
with the two bonds of the one oxygen, and the other three 
replacing the three hydrogen atoms in the three molecules 
of water. All acids may be thus classed in one of these 
two types, hydrochloric acid being the type for all acids 
containing no oxygen, while those containing oxygen are 
relegated to the water type. The student is earnestly 
advised to get the formulas of a number of acids — inor- 
ganic acids — from any text-book, and classify them into 



94 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

the two types mentioned. There are other types to which 
reference may be had later on. 

Now a step further. Salts, in a general sense, may be 
said to be acids in which the hydrogen has been replaced 
by a metal. Sulphate of magnesium, MgSO^, is a salt de- 
rived from sulphuric acid, H2S0^, by replacing the hydrogen 
with magnesium. If the H in HNO3 ^^ replaced by sodium, 
Na, NaNOg, sodium nitrate, results; in a like manner, 
NaCl, sodium chloride, common table-salt, is HCl with the 
H removed and supplanted by Na, sodium or natrium. 

In the case of monad metals, there must be as many- 
atoms as there are hydrogen atoms in the acid : 

HOI with Na yields NaCl, Sodium chloride. 

HNOg with Na yields NaNOj, Sodium nitrate. 
H^SO^ with Na yields Na.SO^, Sodium sulphate. 
H3pO^ with Na yields NagPO^, Sodium phosphate. 

When the metal has more than one bond an equivalent 
of the acid must be employed: 

2IIC1 with Ca yields CaCl^, Calcium chloride. 

2IINO3 with Ca yields Ca(N03), Calcium nitrate. 
H2SO4 with Ca yields CaSO^, Calcium sulphate. 

2H3PO, with 3Ca yields CagCPOJ^. Calcium phosphate. 

To make the salt calcium chloride we must remove the 
hydrogen from two molecules of hydrochloric acid, be- 
cause Ca is a dyad ; for the same reason we must employ 
two molecules of HNO3 to make calcium nitrate. To 
make the calcium sulphate only one H^SO^ is necessary, 
because that contains the necessary H^. In trying, to thus 
write the formula for phosphate of calcium the student 
may be puzzled a little at first, but he will have no trouble 



PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 95 

if he will only remember that the base in the salt must 
have as many bonds as there are bonds in the base of the 
acid, and that he may employ more than one molecule of 
the acid if necessary. Ca has two bonds, but there are 
three hydrogens to be replaced. The easiest thing to do 
is to find the lowest multiple of the two numbers, in this 
case 2 and 3, which is 6. Six, then, is the number of hydro- 
gens that there must be in the acid, hence we take the acid 
twice, 2H3PO^. The base of the salt, then, also must con- 
tain six bonds; and 3Ca have six bonds, hence the formula 
of the salt will be Ca3(P0j2. In thus producing salts from 
acids there is merely an interchange of bases, of course 
governed by the number of bonds of the respective bases. 
It may be well to state here that a salt is by some looked 
upon as consisting of two parts, a hase and a radical, or, as 
some chemists prefer, of a basylous and an acidulous rad- 
ical. In potassium nitrate, KNO3, the K is the base or 
basylous radical, while the NO3 is the radical, or acidulous 
radical. Acids are salts, but the term acid is specific, and 
means a salt containing hydrogen as its base. 

The salts thus far spoken of are all neutral salts — that 
is, they are such that are derived from acids by replacing all 
the hydrogen of the latter by a metal. Now, it is possible 
to -remove only part of the hydrogen with a metal, as is 
the case with bicarbonate of sodium, NaHOOj, which is 
carbonic acid, H^COg, with half its H replaced by sodium. 
Cream of tartar, KHO^H^Og, is obtained by removing one 
H from tartaric acid, H^C^H^Og, and putting one of potas- 
sium in its place. Such salts are distinguished from the 
neutral salts by special terms; they are acid salts or Usalts. 
We distinguish another kind of salt, the double salt, exem- 
plified in Rochelle salts, the tartrate of potassium and 



96 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

sodium. Tartaric acid, H^C^H^Og, containing two hydro- 
gen atoms in the base, has one replaced by potassium and 
the other by sodium, KNaO^H^Og. Here the base consists 
of two metals. 

The student is recommended to read again, very 
carefully, the chapter on Chemical Notation and 
Nomenclature. 

But to return to sulphur. As already said, in H^S we 
have a valuable reagent. When it comes in contact with 
the solutions of a great many of the metals it gives its 
sulphur to them, forming characteristic precipitates. Thus 
lead with H^S gives a very black precipitate, while zinc 
yields a white one and arsenic a yellow one. These pre- 
cipitates are sulphides — that is, the direct union of a metal 
with sulphur alone. H^S may be made by acting on sul- 
phide of iron with sulphuric acid: FeS + H^SO^ =FeSO^ 
+ HjS. It has a very disagreeable odor, is soluble in 
water and in water of ammonia. The latter solution is 
also an official test-solution, that called ammonium sul- 
phide. Sulphuretted hydrogen is the chief constituent of 
sulphur-waters. The sediment found in these waters at 
times is sulphur, due to the decomposition of the gas, 
setting the sulphur free. 

The other acids of sulphur will be considered in the 
chapters on acids. 

Phosphorus. 

Occurrence in Nature. — Phosphorus never occurs in a free 
state in Nature, but is most usually found in the form of 
phosphates of some of the metals, principally of calcium, 
sodium, potassium, iron and aluminum. The soil contains 



PHARMACEUTICAL AI^D MEDICAL CHEMISTRY. 97 

a considerable quantity, and is fertile in proportion to the 
amount of it present. Soil, it should be understood, is the 
result of the disintegration and tumbling down of the 
ancient unstratified rock, and of some of modern origin, 
and these ancient rocks having contained phosphorus as 
phosphates, the latter is now present in soil as a conse- 
quence. And that this is so is another illustration of the 
sublime economy of nature, for phosphorus is an essential 
constituent of plant food. Most plants could not exist 
were it not for the presence of phosphorus in the soil — 
this is shown on fields in which there have been many suc- 
cessive crops without the aid of artificial fertilizers — each 
successive crop becomes less abundant, because each previ- 
ous one has diminished the amount of phosphorus present. 
The phosphorus which thus passes into the organism of 
plants finds its way into the bodies of animals to which 
plants serve as food. The bones of animals are made up 
almost wholly of phosphate of calcium, thus indirectly de- 
rived from the soil through the intervention of the plant 
world. The salt plays an important part in the animal 
frame, the skeleton of man and animals being largely com- 
posed of it. 

Source. — Phosphorus is chiefly obtained from bones, 
which contain 60 per cent of phosphate of calcium, or 
tricalcic phosphate, Csi^(POJ^. Formerly it was obtained 
from urine. Brandt, of Hamburg, a chemist, discovered it 
in this excretion in 1669, and for a long time that was its 
only source. On account of the small yield it was very 
scarce and expensive at first. 

Preparation. — Nowadays phosphorus is prepared from 
bones, which are first calcined and then reduced to a fine 
powder. Calcination removes the fat and all other organic 



98 PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 

matter which heat will destroy, leaving as residue a salt 
which is mainly calcium phosphate. The powdered cal- 
cined bones are then mixed with sulphuric acid diluted 
with water, and the mixture allowed to stand, to per- 
mit the insoluble sulphate of calcium which is formed to 
deposit. The tricalcic phosphate (having three atoms of 
calcium) Csi^(PO^)^, becomes converted into a monocalcic 
(mono = one) phosphate, which is soluble and remains in 
solution: Ca3(P0J, + 2H,S0, = CaH,(POJ, + 2CaS0,, 

After standing for several hours the supernatant liquid 
is poured off from the deposited calcium sulphate, filtered 
and evaporated to a syrupy consistency, mixed with pow- 
dered charcoal, and the whole thoroughly dried in a vessel 
exposed to a high temperature. When quite dry the resi- 
due is introduced into a stoneware retort and carefully 
heated again; vapors of phosphorus are distilled and care- 
fully collected under water 

3CaH,(P0J, + 50 = Ca3(P0j, -f 4P + 6H,0 + SCO,. 

The Oa3(POj2 remains in the retort together with some 
charcoal; the mixture is incinerated, thereby removing the 
charcoal and fitting the bone phosphate for treatment with 
sulphuric acid, to convert it again into the soluble phos- 
phate. This method is the one usually employed, and by 
it 100 pounds of fresh bones yield from 6 to 7 pounds of 
phosphorus. 

Another method resembling the above is coming into very 
frequent use. Instead of mixing the soluble phosphate with 
charcoal alone, sand is added and the process conducted 
as above. (Sand is mainly oxide of silica) : 20aH4(POj2 + 
2SiO, + 100 = 20aSi03 + lOOO + 4P + 4H,0. The sol- 
uble phosphate, CaH^(P0j3 is probably first converted 



PHARMACEUTICAL AITD MEDICAL CHEMISTRY. 99 

during the process of heating into the metaphosphate : 
CslH.^(PO^)^ -\- heat = Oa(P03)2, metaphosphate of cal- 
cium, and 2H2O, water. 

Extreme care must, be exercised in manipulation in 
these processes; they should not be attempted by the 
student. 

Properties. — Phosphorus is a soft, flexible solid, colorless, 
translucent when recently prepared, and of the appearance 
of imperfectly bleached wax. When exposed to light and 
time it gradually becomes less translucent, finally opaque, 
white, yellow and finally red. The latter conditions are 
allotropic ones, which will be alluded to again. Phos- 
phorus has a specific gravity of 1.77 to 1.83, melts at 
44° 0., and boils at 280° 0. When it is slowly cooled it 
sometimes crystallizes in well-formed dodecahedrons. It 
is insoluble in water, soluble in oils, ether, chloroform and 
very soluble in disulphide of carbon. In air it very quickly 
oxidizes and takes fire spontaneously. Its name signifies 
" bearer of light," and was given it on account of its prop- 
erty of being luminous in the dark. " If touched it took 
fire and burned furiously, exhaling a dense white cloud, 
which gathered like fleeces of snow, but, unlike snow, hiss- 
ing like a red-hot iron when touched with water, or, if 
brought into contact with the skin, blistering it like living 
fire." In this way did Brandt refer to its properties after 
he discovered it. They spoke of it at the time as " the son 
of Satan." It is exceedingly inflammable, taking fire from 
the heat of the hand or from a blow or hard rub. Sun- 
shine ignites it immediately. This is due to its great affin- 
ity for oxygen, with which it combines very energetically, 
and, in consequence of which property, it has to be kept 
under water, upon which it has no effect. A stick of 



100 PHAKMACEUTICAL Ai^^D MEDICAL CHEMISTEY. 

phosphorus, when exposed to the air, always emits a whit- 
ish smoke or cloud, due to a slow combustion which the 
phosphorus undergoes with the oxygen of the air, and upon 
which one of the methods for the analysis of the air de- 
pends. The white fumes which it emits when burning 
are PjO^, phosphoric oxide, which will be referred to again. 
The burns caused by phosphorus are exceedingly painful 
and produce sores which are difficult to heal; the greatest 
care must be taken in handling it. 

Allotropic Coi^ditions. — Among the remarkable prop- 
erties of this singular substance is the diversity of its allo- 
tropic conditions, of which it assumes five. The ordinary 
translucent vitreous phosphorus when exposed to light 
under water changes to the first allotropic variety, which is 
white, opaque and less fusible. The second variety is the 
crystalline, obtained by evaporating some of its solutions; 
the thirdf a black, opaque variety, produced by the sudden 
cooling of melted phosphorus : a fourth allotropic condi- 
tion is obtained by suddenly cooling phosphorus when it is 
near its boiling-point, when is yielded a soft, elastic sub- 
stance, analogous to viscous sulphur, described when treating 
of sulphur ; the fifth, called red phosphoi^us, is obtained by 
exposing phosphorus to the sun under water, or by expos- 
ing it to the sun between plates of glass. The latter amor- 
phous variety may also be obtained by heating common 
phosphorus in carbonic acid gas, or in any atmosphere that 
will not act on it chemically. It may be looked Upon as 
the passive condition of phosphorus, as it is devoid of 
many of the energetic properties of the ordinary or active 
variety. It is red in color, heavier than the former, is not 
luminous, nor does it melt at the boiling-point of water. 
It exhales no vapors or odor, oxidizes but very little in the 



PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 101 

a.r, does not change oxygen into ozone, is chemically indif- 
ferent toward other elements, may be handled with impun- 
ity or carried exposed in the pocket, and is not poison- 
ous when administered in doses a hundred times larger 
than would be fatal in the common form (Gr. Wilson). It 
is peculiar also in that it changes into the active form and 
bursts into flame at 500° F. 

Poisonous Properties of Phosphorus. — This element 
is relegated to the list of active poisons, and the student 
cannot be often enough impressed with its toxic proper- 
ties. Taken internally in larger than therapeutic doses it 
acts as a violent poison, being all the more toxic because 
there is no specific antidote for it. Two kinds of phos- 
phorus poisoning are usually distinguished — the acute 
form and the chronic. The former results upon ingestion 
of an excessive amount, while the chronic form affects 
especially workmen employed in the manufacture of 
matches, an industry which is very extensive. Oil of tur- 
pentine has been recommended as an antidote, but some 
authors oppose its use, on the ground that it dissolves the 
phosphorus, rendering it even more active. The stomach- 
pump and emetics and, later, cathartics should be em- 
ployed to eliminate as speedily as possible the phosphorus 
in a mechanical way. It must be borne in mind that this 
poison is soluble in oils or fats, and hence these should 
not be given, not even milk, since that contains considerable 
fat. 

Experiments. — The student is fully aware by this time 
of the danger connected with the handling of phosphorus, 
but yet he should have enough confidence to undertake 
a few experiments which will make him learn to exercise 
care in the manipulation of a dangerous substance. 



102 PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 

Put into a flask, having a well-fitting cork, a small piece 
of phosphorus by means of small pincettes, add two or 
three drams of ether and allow to stand for a few days, 
shaking occasionally. The ether will dissolve most of the 
phosphorus. Several drops of this solution poured upon 
the hands and these quickly rubbed together will cause 
the ether to evaporate and the phosphorus to remain upon 
the hands in a state of minute division. The phosphorus 
soon begins to become luminous, causing the hands to 
shine in the dark, the luminosity becoming more intense 
upon rubbing the hands, as a fresh surface of phosphorus 
is thus continually presented to the oxygen of the air. 
Heat is produced, but it is too feeble to occasion ignition; 
it is slow combustion. The phosphorus unites chemically 
with the oxygen of the air, producing one of the oxides of 
phosphorus, which in turn combines with the water in the 
air to produce phosphoric acid. If a lump of sugar be 
moistened with the ethereal solution of phosphorus and 
thrown into hot water, the heat of the latter causes the 
ether to volatilize, and the phosphorus rises to the top and 
there inflames spontaneously. In this case the combustion 
is brisk and complete, and the phosphorus takes up a 
larger amount of oxygen than above, forming the phos- 
phoric oxide, P2O5, and this with the moisture of the air, or 
with water, produces phosphoric acid. In the preceding 
experiment the oxide produced was the phosphorous Oxide, 
P2O3, which is always produced when phosphorus com- 
bines slowly and incompletely with oxygen, while, when 
the oxidation is complete — that is, when it is accampanied 
by flame — the higher phosphoric oxide, ^fi^, is always 
formed. 

Pour some of the ethereal solution of phosphorus upon 



PHAEMACEUTICAL AKD MEDICAL CHEMISTRY. 103 

fine blotting-paper, and as soon as the ether will have evap- 
orated the paper will ignite spontaneously. 

If a little finely-powdered charcoal or soot is sprinkled 
over a small piece of phosphorus the latter melts after a 
while and spontaneously inflames. The charcoal causes 
this combustion; because of its porosity it absorbs oxygen 
from the air, imparts it to the phosphorus, and being also 
a non-conductor of heat prevents the cooling of it. 

A piece of phosphorus in a wine-glass will melt if hot 
water is poured upon it, but will not ignite because of the 
absence of air. If air be blown very carefully through a 
long tube upon the phosphorus a combustion will take 
place which is especially visible in the dark. An oxide of 
phosphorus is formed, but a much lower one than in any 
of the experiments, the phosphorus being in excess of the 
oxygen, in this instance, P^O. The three oxides men- 
tioned thus far, the P^O, P^Og and P^O^, will receive more 
attention later on, under Phosphoric Acid. 

The P^O may also be obtained by gently heating a small 
piece of phosphorus placed in the middle of a glass tube 
about a foot or 15 inches long. When ignition commences 
the heat should be withdrawn. The combustion is feeble 
and imperfect while the tube is held horizontally, because 
the heavy smoke, consisting of phosphoric and phosphorous 
oxides, passes off slowly, allowing the admission of only a 
small quantity of air. As soon as the tube is inclined the 
combustion becomes more vivid, and when the tube is held 
perpendicularly it becomes perfect, because of the draught 
of air through the tube. In this wise phosphorus may be 
oxidized to any of the three degrees. 

Uses of Phosphorus. — In the manufacture of matches we 
have one of the chief uses for phosphorus. Vast quantities 



104 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

are consumed in this way. In making the matches the 
wood is cut by machinery, the ends first tipped with sul- 
phur, which is in a molten condition for the purpose, and 
then with an emulsion of phosphorus in ordinary glue, to 
which is added a little nitrate of potassium, oxide of man- 
ganese or chlorate of potassium. The latter bodies are all 
rich in oxygen. In igniting a match, the friction-heat 
produced by striking it against a surface is sufficiently 
high to cause the phosphorus to kindle and unite with the 
oxygen furnished by the nitrate or chlorate of potassium. 
The heat and flame produced by this chemical union be- 
tween the phosphorus and oxygen are sufficient to cause the 
sulphur to burn, which in turn ignites the wood. Not 
only is the manufacture of matches dangerous from the 
explosive nature of the materials used, but also because of 
the corrosive phosphoric vapors, which produce at times 
among the laborers a distressing disease known as caries of 
the lower-jaw. Improvements in the methods employed 
have lessened the danger of this dread disease. 

In treating of the occurrence in nature of phosphorus, 
we learned how essential it was to plant and animal life, 
how it came to be in the soil, and how it found its way 
through the vegetable world into the animal, where its 
function is most important in that it builds up the bony 
structure. It is also an important constituent of the brain 
and nervous system. After continued brain exercise there 
is always an increase in the proportion of phosphoric 
products in the liquid excretions. 

Phosphorus in Pharmacy and Medicine. — Phosphorus is 
official in four forms : as phosphorus in its unaltered state, 
as a solution in the form of Phosphorated Oil, in a minutely- 
divided form in the Pills of Phosphorus, and in a state of 



PHAEMACEUTICAL AKD MEDICAL CHEMISTRY. 105 

combination with oxygen and hydrogen in Phosphoric 
Acid. There are other compounds besides these in which 
phosphorus occurs, but they are not made directly from 
phosphorus. 

The Pharmacopoeia directs phosphorus to be kept under 
water, in a secure and moderately cool place, protected 
from light. 

When phosphorus is intended for medicinal use it should 
be absolutely pure. The commercial article sometimes 
contains a little arsenic or sulphur, or both, which render 
it totally unfit for the purposes of medicine, and the pres- 
ence of which should be strenuously guarded against. To 
detect arsenic, a portion of phosphorus should be dissolved 
in nitric acid, water added, and the solution evaporated 
until all superfluous nitric acid is dispelled. Before the 
solution (which should be somewhat diluted) has thoroughly 
cooled a stream of hydrosulphuric acid gas, H^S, should 
be passed through it for half or three quarters of an 
hour. If arsenic is present a lemon-yellow deposit will be 
formed within twenty-four hours, abundant in proportion 
to the quantity of arsenic. If no deposit forms within that 
time, it may be assumed that there was no arsenic present. 
The Pharmacopoeia allows a slight quantity of sulphur to be 
present in phosphorus. If to the above solution a few 
drops of test-solution of chloride of barium be added, not 
more than a slight opalescence should make its appearance. 
The opalescence is due to the presence of sulphuric acid, 
which is formed by the action of the nitric acid upon traces 
of sulphur which are present. 

The dose of phosphorus is from yf^- to -^ grain. In 
large doses it acts as a poison. The medicinal value of 
phosphorus as a nervous stimulant seems only to be 



106 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

obtained by administering it in a free state. The oxide of 
phosphorus, or phosphoric acid, has a different action, and 
hence the necessity of preventing the oxidation of the 
phosphorus. The pills and the phosphorated oil are in- 
tended for the administration of phosphorus in a free 
state. 

Phosphorated Oil is prepared by heating expressed oil 
of almond to about 250° C, allowing to cool, filtering, 
adding the phosphorus, heating again in a water-bath until 
the phosphorus dissolves, allowing to cool and adding 
ether. Phosphorated oil, when fresh, should be clear and 
colorless, or only slightly colored, phosphorescent in the 
dark, and have the taste and odor of phosphorus. The 
oil is first heated to expel air or water, which, if present, 
would oxidize the phosphorus. The ether, besides serv- 
ing to preserve the oil, also renders its taste less dis- 
agreeable. A good way of administering phosphorated oil 
is in milk or in the official emulsion of almonds; the dose 
is from 1 to 5 minims, the oil containing 1 per cent phos- 
phorus. 

Phosphorus Pills contain y^ grain each, and are made 
by dissolving the phosphorus in chloroform, adding this 
chloroformic solution to a mixture of marshmallow and 
acacia in a mortar, and quickly making a mass with glycerin 
and water. To prevent the oxidizing action of the air 
they are directed to be coated with balsam tolu which has 
been dissolved in stronger ether. The pills are shaken 
with a sufficient quantity of the tolu-ether solution and put 
away on plates to dry. The balsam forms a coating which 
is impervious to air or moisture. The pills should be kept 
in small, well-stoppered bottles. In making the solution 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 107 

care should be taTcen not to use heat, as ether is very 
inflammable and volatile. 

Phosphoric Acid also is made directly from phosphorus, 
but that will be referred to in the chapter on acids. 

Boron. 

Boron is of some importance in pharmacy, being the 
chief chemical constituent of the important and much used 
borax and boric acid, and of all borates. 

Occurrence in Nature. — Boron is never found in the free 
state in nature, but most abundantly in boric acid and in 
sodium borate. The boric acid occurs in solution in the 
hot lagoons of Tuscany, while borax forms a crystalline 
deposit in many of the lakes of California and in those of 
Thibet and Persia. The borax obtained from the latter is 
imported in a crude state under the name of tincal, which 
is crystallized and purified here, though the main supply 
of our market is obtained at present from the lakes of 
California. A native borate of calcium is found in 
Southern Peru; this and the native boric acid from Tus- 
cany furnish a large proportion of the borax in the market. 
Besides these sources, horax springs furnish considerable 
borax. It is a peculiar fact that borax springs always con- 
tain ammonia. 

Preparation. — Boron is obtained by heating one of its 
compounds, boric acid, preferably, with magnesium in a 
suitable tube, and by continued washing in dilute hydro- 
chloric acid, washing out the borate and boride of mag- 
nesium which are formed. 

Boric Acid. — There are many compounds containing 
boron, but we confine ourselves to the two of importance 
in pharmacy, namely boric acid and borax. The lagoons 



108 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

of Tuscany formerly furnislied the greater part of the 
boric acid in commerce, but at present the most of it is 
obtained from the borax found in the lakes of California 
by decomposing it with hydrochloric acid. 

Borax is a biborate of sodium, NajB^O^lOH^O, which 
when treated with either hydrochloric or sulphuric acid, 
while in hot solution, has its sodium displaced by the acid, 
the hydrogen of the acid combining with the boric radical, 
forming boric acid, thus : 

{m.Bfl^ + lOH.O) + n,SO, = Na.SO, + 4H3BO3 + 
5H,0, or (Na,B,0, + lOH.O) + 2HC1 = 2NaCl + 
4H3BO3 + 5H,0. 

In the first instance sulphate of sodium is formed as 
a by-product; in the second, a chloride. Both these 
salts are very soluble and remain in solution, while the 
much less soluble boric acid separates upon cooling, and 
is purified by redissolving in pure water and again crystal- 
lizing. 

As thus obtained, boric acid is in transparent six-sided 
plates or scales, soluble in 25 parts of water; much more 
soluble in hot water. It is a weak acid compared with 
the other mineral acids, and turns blue litmus paper not 
red, like other acids, but only a wine-red color; while 
turmeric paper (porous paper soaked in solution of tur- 
meric) becomes brown in its contact with it. Alkalies 
have nearly the same effect on turmeric paper, but the 
brown color disappears on the addition of stronger acids. 
Turmeric paper turned brown with boric acid does not lose 
its color with acids, but turns bluish-black with ammonia- 
water. 

Boric acid, added to alcohol, imparts to the flame of the 
latter a green color. This is a characteristic property of 



PHARMACEUTICAL A^T) MEDICAL CHEMISTRY. 109 

boric acid. The crystallized acid contains water of crys- 
tallization — H3BO3 + HjO — and when heated melts in this 
water, which volatilizes, leaving a glassy bead of an- 
hydrous boric acid, which is much utilized in blowpipe 
analysis. A piece of platinum wire, with a loop on the 
end, if wetted and dipped into boric acid, affords a con- 
venient means of exposing boric acid to the blowpipe 
flame. If a stream of air is directed through the blowpipe 
into the flame of a spirit lamp, or Bunsen-burner, and the 
wire with the acid brought near to the flame, the acid will 
first melt and swell in its water of crystallization, and 
finally will be converted into a transparent glassy bead. 
This bead consists of the oxide of boron, probably B^Og, 
which, in its molten condition, has the property of dissolv- 
ing many metallic oxides with very marked and character- 
istic colors. If this glassy bead be moistened and dipped 
into chalk or litharge, or into almost any oxide, and again 
heated to melting, these substances will unite most inti- 
mately with the boric oxide, and be dissolved by it, and 
assume a glassy, or, better, vitrified appearance. Most 
of the combinations of boric acid with oxides or bases 
become vitreous on heating — that is, they melt together, 
forming a white or colored glass. Chromium salts thus 
give a green color, manganese an amethyst, and cobalt a 
blue, etc. 

The official boric acid is only one of the many acids of 
boron, which will receive mention under Borax. 

The blowpipe is a very useful instrument for melting, 
oxidizing, reducing or volatilizing substances in small 
quantities. It is made in various shapes, but consists 
essentially of a metal tube bent a short distance from one 
end and drawn to a point. The proper use of the instru- 



110 PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 

ment requires a little practice, which can be soon acquired. 
The blast should be steady and continuous, and should be 
produced principally by the* muscles of the cheek, the 
respiration not to interfere much. A double combustion 
takes place in the blowpipe flame, a smaller interior cone 
of a blue color and a larger exterior cone of a yellowish 
appearance. The latter is called the oxidizing flame, the 
former, the reduci7ig. If a substance is to be reduced — 
that is, deprived of its oxygen — it is held at the point of 
the inner flame, where it meets with soot or carbon, which 
combines with the oxygen of the substance and escapes as 
carbonic acid, leaving the substance reduced, or devoid of 
oxygen. If, on the other hand, a body is to be oxidized — 
that is, united with oxygen, then it is held at the point of 
the outer flame, where the oxygen of the air can have free 
access to it. It may be good practice for the student to 
convert a piece of lead, placed upon charcoal, into an 
oxide, by exposing it to the outer flame, and then reducing 
it, by exposing the oxide thus formed, to its original 
metallic state. 

Tests for Purity of Boric Acid. — The Pharmacopoeia re- 
quires boric acid, or, as it was formerly called, boracic acid, 
to be free from sodium and from sulphuric and hydrochloric 
acids, which may be present as a result of incomplete wash- 
ing after the acid is separated from its solution with either 
the chloride or sulphate of sodium. Lead, copper and 
calcium should also be absent. Barium chloride solution 
will give a white precipitate with sulphates, insoluble in 
any acid. Solution of silver nitrate yields a curdy white 
precipitate with chlorides, soluble in ammonia-water and 
precipitated upon addition of nitric acid. Calcium may 
be detected by the addition of a solution of ammonium 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. Ill 

oxalate, which produces a white precipitate with soluble 
calcium salts. 

Lead, copper and iron give a black color and precipitate, 
with ammonium sulphide. 

The above tests are all characteristic, and not only ap- 
plicable in these cases, but in many others where the same 
substances are sought. It is well, therefore, that the 
student commit them to memory. 

Uses in Pharmacy and Medicine. — Boric acid is re- 
quired to be in a very fine impalpable powder for most 
medical uses. It is a good antiseptic, and is extensively 
employed in antiseptic surgery. Berated cotton, lint or 
gauzes and bandages are much used as antiseptic dress- 
ings to wounds. It is an excellent means of preventing 
fermentation, and is for that reason added to many liquids, 
to which it communicates but little taste. In form of 
ointment or dusting-powder it is much favored for external 
application. 

Borax. 

Borax is a sodium salt, usually termed in chemical lan- 
guage the borate or biborate of sodium. Its composition 
is expressed by the formula Na^B^O^lOH^O, which shows 
it to be composed largely of water of crystallization. It con- 
tains four atoms of boron, and may be looked upon as a salt 
of one of the many boric acids before referred to. 

As an illustration of the many acids of boron the follow- 
ing may serve : Beginning with one molecule of orthoboric 
acid, II3BO3, we may obtain another by abstracting one 
molecule of water. Beginning with successively two, three 
and four molecules of the orthoboric acid (ortho means 
" straight; " tliat is, *^ the " acid) and abstracting molecules 



112 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

of water as long as possible, we get a large variety of boron 
acids, viz.: 



1) 

H3B03 

-H, 


2) 
H.B,0. 
-H, 


3) 
H.B.O, 
-H, 


4) 
H„B,0„ 
-H, 


HBO, 


H.B,0. 
-H, 


H,B,0. 
-H, 


-H, 




H,B,0. 

) 


H.B,0, 
-H, 


H,B.O.. 
-H, 




H,B,0. 
-H. 


H.B.O, 
-H, 




HB,0. 


H.B.O. 
-H, 


(Chandler 


H,B.O, 



The last acid, H^B^O,, may be looked upon as the one 
furnishing borax or borate of sodium by having its hy- 
drogen replaced by as many sodium atoms, ISTa^B^O,. The 
lOH^O are taken up during crystallization. H^B^O, is 
called the pyrohoric acid, but the term is applicable to any 
of the other acids obtained by abstracting water from the 
ortho acid by heating, pyro meaning "fire;^' that is^ in 
this case, an acid obtained by heating another. 

Pyrophosphoric acid is another example of a pyro acid. 

Borax, as already mentioned, is obtained principally 
from the borax lakes in California, where it occurs as a 
crystalline deposit in the mud at the bottom of the lakes. 
The large crystals are washed with water, dissolved and 
crystallized, thereby yielding an almost absolutely pure 



PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 113 

salt, which, when powdered, constitutes the powdered borax 
of commerce. 

Borax is also made from the boric acid obtained from 
Tuscany by fusing it with dried sodium carbonate and 
crystallizing the hot solution of the residue. 

The official borax is in colorless, shining, monoclinic 
prisms, somewhat efflorescent in dry air. It has an alka- 
line reaction, is soluble in 16 parts of cold and very soluble 
in boiling water, insoluble in alcohol. It is very soluble in 
warm glycerin and honey. 

Tests for the Purity of Borax. — Some of the possible im- 
purities in borax are metals, alkaline earths,, carbonates, 
sulphates and chlorides. 

Sulphuretted hydrogen proves the absence of metals if it 
does not affect a solution of borax. 

The alkaline earths (Ca, Ba, Sr, etc.) are precipitated, if 
present, by a solution of sodium carbonate. Barium and 
calcium, if present, are in minute quantity and dissolved 
in the solution of borax. When sodium carbonate is added 
they are converted into the less soluble carbonates of barium 
and calcium, which precipitate. 

An acid added to a solution of borax causes an ejffer- 
vescence if carbonate is present. (When acids come in 
contact with any carbonate this happens always : Na^OOg + 
2HC1 = 2Na01 + H,003. The H,C03 is carbonic acid, 
which always resolves itself into H^O, water, and COj, 
carbonic acid gas. The escape of the gas produces what is 
known as efervescencBy by carrying with it, in its endeavor 
to get away, portions of the liquid, which when inter- 
mingled with the gas constitute /o(2?/i.) 

Sulphates and chlorides are detected, as in boric acid, 
with barium chloride and silver nitrate, respectively. 



114 PHAEMACEUTICAL AN^D MEDICAL CHEMISTRY. 

Borax enters into many mouth and tooth washes — the 
honey and borax used so extensively, and made by dissolv- 
ing borax in honey, is an excellent form for the use of 
borax as a mild antacid, especially in the sprue or thrush 
of children. It is frequently used to whiten ointments; 
the yellow color which cold cream sometimes takes may be 
prevented by the addition of a little borax solution during 
its preparation. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 115 



Inorganic Acids. 

At this stage of the course the student is earnestly ad- 
vised to read over again very carefully all of the foregoing 
chapters, especially those on chemical philosophy, as he is 
about to enter upon the study of the acids, in which he 
will find the application of the principles of chemistry of 
constant necessity. The non-metallic elements only have 
thus far attracted his attention ; these mastered, the 
student is ready to go deeper into the details of 

The Study of the Acids and Salts. 

When treating of oxygen, we learned that an oxide is 
the union of oxygen with another element. We will go 
further now and divide the oxides into three principal 
groups or classes. The first class includes all those which 
resemble, chemically, the oxides of sodium, potassium, 
barium or ammonium, and others, and are called tasic 
oxides or alkali oxides. The second division comprises 
those oxides whose properties are in opposition to those of 
the first, and which are represented by the oxides of sul- 
phur, phosphorus and carbon — these are the acid oxides. 
The third class is represented by a single compound — 
water, H^O — the oxide of hydrogen. When the first two 
oxides combine — i.e., the basic with the acid — a salt is 
produced: Oxide of calcium, OaO, uniting with the acid 
oxide of carbon, 00^, furnishes a salt — namely, CaOOa. 
In like manner, for illustration, the following basic oxides 
uniting with acid oxides form the salts mentioned : 



116 PHAKMACEUTICAL AKD MEDICAL CHEMISTRY. 



Basic 

oxides. 



Acid 
oxides. 



Potassium 



oxwt^lK.0 + SO, = K,SO„ I 



Sodium 
oxide, 

Barium 
oxide, 

Potassium 
oxide, 



[ Na,0 + 



CO, 



Na2C03, 



Potassium 

sulphite. 

Sodium 
carbonate. 

[BaO + SO. = BaS03, { ^m. 
ZK fi + P,0, = 2K.P0., ] P— t? 



This is one way of producing a salt. 

When the acid oxides come in contact with water (the 
third division of the oxides) union takes place, with the 
formation of acids : 



^"S"1S0. + H,0 = 

^S" JCO^ + H,0 ^ 
"""oat" i^A + 3H,0 = 

Nitric 
oxide. 



Nitric |n.O, + H,0 



Acids. 
H.SO3, 
H2CO3 , 

2H3P0., I ,,i,. 
2HNO3, I ^^ 



Sulphurous 
acid. 

Carbonic 
acid. 

Phosphoric 



Acids are of two principal kinds — the Jiydracids, those 
containing no oxygen, and the oxyacids, those containing 
oxygen and represented by the above. A third division is 
sometimes made, including those represented by arsenious 
acid, ASgOj. The latter had better be termed anhydrides, 
because they contain no hydrogen, and hydrogen is an 
essential constituent of all acids. The word acid is a mis- 
nomer chemically for all substances that do not contain 
replaceable hydrogen in their base. 

We have learned that one way of producing salts is by 
uniting a basic with an acid oxide; another is by replacing 



PHARMACEUTICAL AITD MEDICAL CHEMISTRY. 117 

the hydrogen in acids with metals, thus (Free hydrogen is 
not the by-product in each case, but is assumed to be to 
illustrate the lessen in hand) : 

Acid. Metal. Salt. 

2HN0;, [ + S^^^^"^' ^^« ' =1 ^^^^^' ' + H^ ''''^'''"'' 
Hydrgjhloric, | _j_ ^^^^^ 2n,, = j ZnCl, , Chloride zinc, + 

And a third by replacing the hydrogen with basic oxides, 
thus: 

Acid. Basic oxide. Salt. 

3HNO3 + Sodium oxide, Na^O, = SNaNOs + H^O. 

2HC1 + Zinc oxide, ZnO, = ZnCU + H2O. 

H2SO4 + Iron oxide; FeO, = FeS04 + H2O. 

2H3PO4 + Calcium oxide, 3CaO, = Ca3(P04)2 + SH^O. 

The three ways of making salts, then, are : 1, by uniting 
basic and acid oxides; 2, by uniting metals with acids; 
and 3, by uniting basic oxides with acids. 

In the last-mentioned method it will be noticed that the 
oxide of hydrogen — water — is liberated, and that only the 
acid oxides in the respective acids do the real work for the 
acids — i.e., oxyacids resolve themselves during the union 
into their acid oxides and water : 

2HNO3 = -Nfi, + H,0 
H,SO, = SO3 + H,0 
2H3PO, = P,0, + 3H,0, etc. 

Acids are salts. They are a particular group, and the 
oxyacids always contain the elements of an acid oxide and 
hydrogen oxide. Many of them possess in a marked degree 
the properties to which the term " acid " is applied, such 



118 PHARMACEUTICAL AND MEDICAL CHEMISTRY. ' 

as sour taste, solubility in water, corrosive action, power of 
reddening vegetable colors, and neutralizing alkalies or 
alkaline bases, basic oxides. The most characteristic prop- 
erty of the acids is their power of exchanging their hydro- 
gen for metals or basic oxides to form salts — basic oxides 
are often spoken of as bases — as shown above. Tbus when 
sulphuric acid, which contains hydrogen, sulphur and oxy- 
gen, comes in contact with a metal — zinc, for example — 
the hydrogen is replaced by the zinc, and that which was 
hydrogen sulphate becomes zinc sulphate, the hydrogen 
being liberated. The same will happen when a base comes 
in contact with an acid, only that the hydrogen which is 
set free unites with the oxygen combined with the metal, 
and forms water. 

It must be borne in mind by the student that these 
changes all take place according to the laws of chemical 
combination. The student should also refresh his memory 
regarding, the atomicity, number of bonds, etc., of all the 
elements. 

Salts, and therefore acids, are usually spoken of as con- 
taining a hase and a radical; in H^SO^, for instance, the 
H^ is the base and SO^ the radical; in NaNOg the Na is 
the base and NO3 the radical. (The term base should not 
be confounded with the term as used before.) It would be 
more correct to speak of an acichdous radical, and a hasyl- 
ous radical as constituting an acid — that is, it would be 
more rational, as an acid and a hase when united form a 
salt, and both may be looked upon as radicals or roots. 

In writing salts the base, as well as the radical, has a 
certain number of bonds, whether each consists of only one 
element or of more. In the following there is only one 
element in each, the base and the radical, and consequently 



PHARMACEUTICAL Al^D MEDICAL CHEMISTRY. 



119 



the base and radical haye each as many bonds as their 
respective elements : 

Radical. 
Chloride' 
Bromide' 
Iodide' 
Chloride" 



Base. 
Sodium' 
Hydrogen' 
Potassium' 
Calcium" 



NaCl 

HBr 

KI 

CaCL 



In the following there is one element in the base and 
more than one in the radical. The elements in the radical 
form a group which may be looked upon as behaving as a 
single element does and together having a certain number 
of free bonds. 





Base. 


Radical. 






HN03 


H' 


(NO3)' 


nitric acid 


) 


H,SO, 


H/' 


(SO.)" 


sulphuric acid 


f Inorganic. 


H3PO, 


H3"' 


(PO.)'" 


phosphoric acid 


) 


HC.HaO, 


H" 


(0,H30,)" 


acetic acid 


^ 


H.C,H,0, 


H/' 


(O.H^OJ" 


tartaric acid 


^ Organic. 


HsCeH.O, 


H3"' 


(C.H,0,)"' 


citric acid 



The (NO )' has one bond, the (SOJ" two, and the 
(POJ'" three, etc.; these radicals interchange in the dif- 
ferent combinations without altering their relative propor- 
tion or position. The student should study the quanti- 
valence of the above-mentioned acid radicals and commit 
them to memory. In order to make salts from these or 
other acids it is only necessary to replace the hydrogen 
with an equivalent quantity of some metal, and to remem- 
ber that the hydrogen alone can be replaced. 

Bases, like radicals, may consist of more than one 
element : 



120 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Base. Radical. 

Sodium bicarbonate (NaH)" (CO3)" NaHCOs 

Potassium bitrartate (KH)" (C4H4O6)" KHC4H4O, 

Sodio-potassic tartrate (KNa)" (C4H4O6)" K]SraC4H408 

Acid calcium phosphate (CaH)"' (PO4)'" CaHPO* 

These salts are known as acid or bi-salts when they con- 
tain some unreplaced hydrogen, and as double salts when 
the hydrogen of a dibasic or tribasic acid is replaced by 
two metals, as in Rochelle salt, KNaO^H^Og , etc. Acids 
having one replaceable hydrogen atom are called mono- 
basic, as HOI, HNO3 ; when they contain two replaceable 
atoms, dibasic, as H^SO^ ; when three, tribasic, etc. The 
same terms apply to salts. 

In writing the formulas for salts or acids, the base occu- 
pies the left and the radical the right. Thus, sulphate of 
sodium is written Na^SO^ , and not SO^Na^ , or O^SNa^. The 
atoms occupy a definite position in their arrangement in 
the molecule. We may express this relative and constant 
position of the atoms by means of 

Graphic Formulas. 

When we write H2SO4 we employ a rational formula — 
i.e., rational, because it shows us in a rational way at a 
glance how many hydrogen atoms are replaceable and how 
many bonds the radical has, etc. If we should write 
O4SH2 , that would imply that sulphuric acid contains 4 
atoms of oxygen, 1 of sulphur and 2 of hydrogen, but it 
would tell us nothing further than that. 

The following graphic formulas of the principal acids 
should be remembered by the student: 



PHARMACEUTICAL Ai^D MEDICAL CHEMISTRY. 121 

H,SO, = )S C HCl = H~C1 

HNO3 = H-O-N ^ H3P0,= H-0->P = 

This shows the number of bonds of each element to be 
satisfied or united with the bond of some other element, 
and the positions of the atoms in the molecules. In H^SO^, 
for example, the S has six bonds distributed among the 
three oxygen atoms, each of which atoms has two bonds. 
The hydrogen always occupies the left-hand position, and 
in the case of oxyacids is ahuays united to oxygen. 

Graphic formulas of salts are written exactly as those of 
the acids are, except that the metals occupy the place of 
the hydrogen. 

NajSO^ would be written graphically thus : 

Na-O. ^ 
Na-O/ "=" 

0a3(P0j2 from two molecules of phosphoric acid, 
n3P0,: 

H-0\ ^_ .Ov 






H-0 



Oa< 







H-0-^p=0 Oa<^-^P=0 



H-0 



0, 



Calcium being a diad and phosphoric radical a triad, 
we must take three of the former and two of the latter to 
satisfy all bonds. 



122 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

It was at one time supposed that all acids contain oxy- 
gen, and the element known as oxygen was so termed be- 
cause of that belief, the term meaning acid generator. We 
are acquainted at present, however, with many bodies 
which exhibit all the properties of acids and yet contain 
no oxygen. The combinations of the halogen elements 
with hydrogen are such bodies — hydrochloric acid, HCl; 
hydrobromic, HBr; hydriodic, HI, etc. These are the 
hydracids. The proportions of the two elements in each of 
these acids cannot vary as the elements do in the oxyacids. 
As illustrations of varying quantities of elements in some 
of the latter, the following may serve : 

II2SO3, hydrogen sulphite or sulphurous acid. 

H^SO^ , hydrogen sulphate or sulphuric acid. 

HNO2 , hydrogen nitrite or nitrous acid. 

HNO3 , hydrogen nitrate or nitric acid. 

The oxygen varies in quantity and determines the names 
of the acids and the salts obtained from them. The stu- 
dent is advised here to read over again what was said on 
chemical nomenclature and writing of salts elsewhere. 



The inorganic acids are never made by the pharmacist; 
their manufacture on the large scale is an important and 
one of the most extensive branches of the chemical in- 
dustry. The manufacturing chemists send the acids into 
the markets usually in three qualities, the common or 
commercial f used for all else than for medicinal or ana- 
lytical purposes; the medicinally 'pure, abbreviated if.P., 
used for internal administration, and the chemically j^ure, 
abbreviated C.P., intended for analytical purposes where 
absolute purity is essential. The latter is almost wholly 



l>HARMACEUTiCAL AND MEDICAL CHEMISTRY. 123 

used in pharmacy for prescription use, and in making 
preparations containing acids, since it is nearly as cheap 
as the medicinally pure. One of the most difficult and 
expensive parts of the manufacture of the acids is the 
removal of impurities, and for purposes in which the im- 
purities are of no consequence the process of purification is 
wholly omitted, yielding the common or commercial acids. 
Very often the presence of minute traces of some kinds of 
impurities will not affect the value of the acids for medici- 
nal purposes, so that the traces are not removed, but only 
the greater bulk of the impurities, yielding acids which 
answer the purposes of medicine very well, but which are 
yet unfit for delicate analytical uses. For the latter pur- 
pose all traces of impurities must be removed, and to do 
that requires more skill and expense than to free the com- 
mon acids from the greater bulk of their impurities. In 
most cases it is not possible to remove all impurities at 
once from the crude acid, hence the amount of work is 
greater for the production of the medicinally pure than 
for the common. The same is true of the chemically pure 
over the medicinally pure. At one time the cost of the 
production of the chemically pure was much greater than 
that of the medicinally pure, but of late, improvements in 
the methods of purification have brought the price of the 
former so near that of the latter that pharmacists now 
usually purchase the C.P. 

The labels should not satisfy the conscientious pharma- 
cist as to the purity of the acid which he purchases. It is 
an easy matter to apply the simple tests given in the Phar- 
macopoeia for the detection of impurities. The mineral 
acids should never be kept in any other than glass-stop- 
pered bottles ] cork is acted upon and quickly contami- 



124 PHARMACEUTICAL AKD KEDICAL CHEMISTRY. 

nates the acid. A special bottle, called acid-bottle, usually 
made of green glass and very strong, is used as acid con- 
tainer. The neck and stopper are usually well ground and 
fit very accurately^ for which reason it is often difficult to 
extract the glass stopper. To do this successfully, all that 
is usually necessary is to remove the wax or lute from 
around the stopper and strike the side of the stopper 
gently with the wooden handle of a spatula, at the same 
time pulling upward on the stopper. If this will not 
accomplish the purpose, the stopper may be wedged in 
between two closet-doors closing against each other, press- 
ing gently inward and cautiously turning the bottle. Great 
care should he exercised not to break the neck of the 
bottle, else damage to clothing and fixtures will result from 
the spilling of the acid. Should this means not avail, the 
neck of the bottle may be gently turned in the flame of a 
Bunsen burner for a moment. The heat expands the neck 
first, and the stopper may be removed before the heat is 
communicated to it. 

The utmost care must be observed in handling the 
strong acids; some of them — for instance, nitric — may pro- 
duce fire if poured or spilled upon organic bodies. They 
are all very corrosive and caustic, attacking and destroying 
everything they come in contact with. It is always best 
to have an alkali on hand, in case it becomes necessary to 
neutralize them; ammonia-water neutralizes most quickly, 
bicarbonate of sodium or chalk will answer well also. 
The solutions of soda and potassa neutralize well, but 
they, too, are very caustic and may do damage if used in 
excess. 

Antidotes to Mineral Acids. — The acids are all very 
powerful poisons and produce the most painful and dan- 



PHARMACEUTICAL Ai^D MEDICAL CHEMISTRY. 125 

gerous effects on the mucous membrane and stomach. If 
they are taken at any time accidentally, large draughts of 
alkaline liquids that do not corrode should be given, fol- 
lowed with oil. Sodium bicarbonate made into a milk 
with water should be given slowly, if at hand, or any other 
chemical that will neutralize the acid without itself being 
injurious. The 00^ which is disengaged usually escapes 
through the oesophagus and mouth, and because of the dis- 
engagement of the gas where carbonates are given the lat- 
ter should not be administered too copiously, but rather in 
small quantities frequently. The gas may cause undue dis- 
tention and distress if liberated too suddenly. Soap is 
an excellent antidote, given in strong solution. The oil, 
which should follow, obtunds the action of the acid upon 
the delicate membranes. 

Medical Properties of the Inorganic Acids. — Externally 
applied the inorganic acids are very corrosive, and should 
be used with great care. For internal administration they 
are usually given in a diluted form for their refrigerant and 
tonic properties. They are apt to injure the dental struc- 
ture by attacking and dissolving the substance of the 
teeth, and for this reason should always be taken in plenty 
of water and through a glass tube in such a way that they 
do not come in contact with the teeth. 

Sulphuric Acid. 

We know by this time that an acid, aside from its char- 
acteristic physical properties, is a chemical compound 
containing hydrogen as its base, which hydrogen is replace- 
able by metals. In the same way that we can replace this 
hydrogen in the acids by metals and produce salts, we can, 



126 PHAKMACEUTICAL AITD MEDICAL CHEMISTRY. 

reversely, replace the metals in salts by hydrogen and obtain 
the acids. This will become clearer, perhaps, by illustration. 
If we treat the salt nitrate of sodium, NaNOg, with sul- 
phuric acid, H2SO4, two things happen — the H, is replaced 
by the Na, two atoms of which are taken, and the two 
atoms of sodium are replaced by an equivalent of hydrogen, 
Hj. In other words, there will be simply an interchange 
of bases; the H^SO^ forms the salt Na^SO^, sulphate of 
sodium, and the nitrate of sodium becomes HNOg, nitric 
acid : 

H,SO, + 2]S^aN03 = 2HNO3 + Na.SO,. 

In this manner is nitric acid made. In fact, all of 
the acids may be made in this way, by bringing an acid in 
contact with a salt containing the corresponding acid 
radical. 

The following acids, made by acting on the correspond- 
ing salts with some other acid, may be cited as examples : 

Acids. Salts. Acids. Salts. 

Hydrochloric, from H,SO, + 2^01 = 2HC1 + Na.SO, 
Hydrocyanic, '' HCl + AgOy = HCy (or HON) 

+ AgOl. 
Acetic, HNO3 + KCJIfl, = HC.HgO, + KNO3 

In the above reactions the Na^SO^, AgCl and KNO3 are 
by-products and the acid the primary product. 

The question may be put by the student : Are all acids 
made from some other acid ? Must there not be some acid 
or acids (the source of all other acids) which is or are not 
made from some other acid? The logical answer would be 
that if all the acids are made from other acids, very soon 
there would be no acids at all, and that therefore some acid 
must have its source in something which is not an acid. 



PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 127 

The latter is true of sulphuric acid, which is the most im- 
portant of all the inorganic acids, principally because it is 
the source of many other acids, and is not itself made from 
another acid. The student will better understand this as 
we go on. 

The method of manufacturing sulphuric acid to-day is 
essentially, with some modifications, the same as that 
experimentally employed by Lavoisier in 1774 and 1775. 

Preparation. — By burning sulphur in air it takes up 
oxygen and becomes the oxide of sulphur, SO^. The heat 
produced is utilized in suitable chambers to decompose 
sodium nitrate ; this decomposition yields oxygen, which 
is taken up by the SO^ to form SO3. The SO3 fumes, 
coming in contact with watery vapors, unite with them, 
producing sulphuric acid, H^SO^, in a diluted form. The 
following equations will serve to demonstrate this more 
clearly. 

(1.) S + 0, (Air) == SO,. 

(2.) 2NaN03 -f heat = Na,0 + N^O, + 30, or 

(2a.) 2Na]Sr03 + H,SO, = Na.SO, + 2HNO3. 

(26.) 2HNO3 + heat = H,0 + N,0, + 30. 

(3.) N,0, + 0, (Air) = N,0, 

(4.) 2S0, + N,0, = 2SO3 + N,0,. 

(5.) SO3 -f H,0 (Steam) = H,SO,. 

If the SO2 is brought in contact with steam HjS03, 
sulphurous acid, will result: 

SO, + H,0 = H,S03. 

To get the higher form of oxidation, the nitrate of so- 



128 PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 

dium is decomposed, the products of decomposition being, 
besides oxygen and water, an oxide of nitrogen, N^O^, 
which has the peculiar property of abstracting oxygen from 
the air to form N^O^ and of giving this up again to the 
SO3 to make SO3, becoming itself again N^O,, when it is 
again ready to abstract a fresh supply of oxygen from the 
air. It thus acts as a carrier of oxygen from the air to 
the SO2, and is generated only in the beginning of the 
process. 

Instead of using sulphur, sulphide of iron, FeS, is often 
employed. In this process it is not necessary that any 
other acid be employed ; it furnishes the acid from which 
nearly all others are made — it is the starting point in the 
acid-manufacturing industry. 

The fumes of SO^ are passed into large leaden chambers, 
where they come in contact with the N^O^, and then with 
steam. The acid thus produced collects at the bottom of 
the chamber, and is not very concentrated. It forms one 
of the varieties of acid found in the market, and known as 
chamber acid, of a specific gravity ranging from 1.40 to 
1.50. When removed to pans, also of lead, and boiled 
down to a specific gi-avity of about 1.70, it constitutes pan 
acid. At that density it begins to act on the lead, the 
dilute acid having no effect on that metal. In order to 
further concentrate it, it is necessary to distil off the 
water in porcelain or platinum or glass retorts. 

The sulphate of sodium, which is the by-product, is re- 
crystallized and sold as Glauber's salt. Sulphuric acid thus 
prepared and purified is an oily liquid of a specific gravity 
of 1.835, colorless, without odor, of a strongly acid reaction, 
and is very caustic and corrosive, soluble in alcohol and 
water with the evolution of heat. If heated to a high 






PHAEMACBIJTICAL AND MEDICAL CHEMISTRY. 129 

degree it volatilizes ; in contact with organic matter it 
becomes black, carbonizing the body by uniting with the 
other elements and setting the carbon free. 

In the crude acid there are present a number of impuri- 
ties, which through incomplete methods of purification are 
often found in smaller quantity in the medicinal and puri- 
fied acids. To guard against the presence of impurities the 
pharmacist should always examine the sulphuric acid for 
lead, copper, iron and arsenic, nitric, hydrochloric and sul- 
phurous acids. In this country the acid is usually made 
from sulphur, but that made abroad is from sulphides of 
iron, or iron pyrites, which are always associated with 
arsenic. The latter, because it is volatile, is usually present 
in the crude acid made from the iron pyrites, and is a dan- 
gerous contamination. 

Tests for Impurities in Sulphuric Acid. — The following 
tests should be memorized by the student, because they are 
for substances which are not present in sulphuric acid 
only, but which may be found in the acids prepared 
directly or indirectly from sulphuric acid. 

To detect lead, a portion of the acid should be poured 
into four volumes of alcohol — a precipitate within an hour 
indicates the presence of lead. 

For iron, when diluted with 10 volumes of water, the 
addition of excess of water of ammonia will give a brownish 
precipitate. 

Copper, if present, gives a blue color with excess of 
water of ammonia. 

Arsenic may be detected by mixing 1 cc. of a mixture of 
1 volume H^SO^ and 2 of water, with 1 cc. test-solution 
stannous chloride, and adding a small piece of pure tin-foil 



130 PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 

— if a coloration appears within one hour arsenic is 
present. 

The acid upon supersaturation with ammonia should 
leave no fixed residue upon evaporation and ignition; this 
would indicate the absence of non-volatile impurities. 

Nitric acid, if present, will produce a brownish or red- 
dish zone between a layer of sulphuric acid, in a test-tube, 
and one of a freshly-prepared solution of ferrous sulphate. 

Hydrochloric acid, if present, gives ^ precipitate with 
solution of sulphate of silver. 

Usfes and Properties of Sulphuric Acid. — The employment 
of this acid is more extensive than that of any other acid. 
It is the strongest and most powerful of the official acids, 
decomposing salts with a marked chemical energy. It is 
the source of most acids and sulphates, and, in a diluted 
form, is a valuable medicament. It is sometimes employed 
externally as an escharotic, but its use for this purpose is 
limited, owing to its tendency to spread on the skin and to 
affect the surrounding tissue. When accidentally dropped 
on the skin its caustic effect may be neutralized by profuse 
use of diluted water of ammonia, or sodium bicarbonate, or 
calcined magnesia. 

In manipulating sulphuric acid it should be particularly 
remembered that it evolves a great amount of heat when 
mixed with other liquids, and that it should ahoays he 
poured i7ito the other liquid, and very slowly, to prevent the 
vessel from breaking by the sudden expansion caused by 
the rapid rise of temperature. 

The sulphuric acid of the U. S. Pharmacopoeia is a liquid 
composed of 92.5 per cent of absolute H^SO^ by weight 
and 7.5 per cent of water. It should be kept in glass- 
stoppered bottles. It is colorless, of oily or syrupy consist- 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 131 

ence, miscible with water and alcohol. It has a specific 
gravity of 1.835 at 15° C, and is vaporized when heated on 
platinum-foil 

Diluted Sulphuric Acid 

contains 10 per cent of absolute acid, and is made by pour- 
ing the acid into water, slowly and carefully, stirring mean- 
while. It has the same properties as the stronger acid, 
except those which depend upon the strength or concen- 
tration of the latter. Its use is chiefly for internal admin- 
istration or for dissolving quinine when quinine is desired 
in the liquid form. 

Aromatic Sulphuric Acid. 

This is a more grateful preparation for the internal use 
of sulphuric acid. It contains 20 per cent of absolute acid 
in alcohol, combined with the aromatics ginger and cinna- 
mon. Tincture of ginger and oil of cinnamon are employed 
by the U. S. P. of 1890. The 1870 Pharmacopoeia em- 
ployed the crude drugs, instead of these their preparations, 
and the finished product contained, as a result, a little tannic 
acid. The aromatic, as the dilute acid, is often employed 
for preparing solution of quinine ; but the presence of tan- 
nic acid in the 1870 Pharmacopoeia product frequently 
caused a turbidity, from the fact that tannic acid precipi- 
tates alkaloids, quinine in this case. To obviate this, the 
Committee of Revision of the Pharmacopoeia in 1880 sub- 
stituted tincture of ginger for the powdered root, and oil 
of cinnamon for the powdered bark, as mentioned above. 

Fuming Sulphuric Acid. — The sulphuric acid described 
above is the ordinary acid of commerce. There is another 
variety known as Fuming Sulphuric Acid, or Nordhausen 
acid, so called because it constantly emits fumes when ex- 



132 PHAKMACEUTICAL AI5"D MEDICAL CHEMISTEY. 

posed to the air; and because it was first made at a place 
called Nordhausen, in Saxony, Germany. This acid is made 
by distilling, in large stone retorts heated to redness, the or- 
dinary sulphate of iron previously deprived of its water of 
crystallization by heat. Polishing-rouge remains in the 
retort, and the fuming acid distils over. It is supposed to 
be 11,^820, or H^SO^SOg — that is, a solution of SO3 fumes 
in H2SO4. The SO3 fumes are constantly given ofC. 

Solid Sulphuric Acid 

is the anhydride, SO3, now to be found in a solid condition 
in the market is soldered boxes of tinned sheet-iron. When 
moisture is wholly excluded this acid has little or no action 
on metals. 

Sulphurous Acid. 

The termination of the first word in this title indicates 
that the acid is a lower sulphur acid than sulphuric acid; 
it denotes that it is the next lower. If we were to take 
one atom of oxygen away from sulphuric acid, H^SO^, the 
acid H2SO3 would result, and in practice that is the precise 
way in which sulphurous acid is made. 

Preparation. — Sulphuric acid is mixed with powdered 
charcoal and heated in a retort or large fiask, and the gen- 
erated gases passed through two bottles containing water, 
the last of which will contain the sulphurous acid sought. 
The first bottle washes the gas. The charcoal or carbon 
acts on the sulphuric acid and takes away one atom of oxy- 
gen from each of two molecules of acid. The H^SOg which 
is left splits up into H^O and SO^; the SO^ and 00^ pass 
through the water in the bottles, saturating the water with 






PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 133 

SO.^, the CO2 escaping. A third bottle containing a solu- 
tion of carbonate of sodium is sometimes employed to 
retain any gas that may not be absorbed by the distilled 
water in the other bottles. The solution of SO^ in the 
second bottle constitutes the product which the process 
was intended to furnish, namely H^SOg. The first bottle 
contains the same but mixed with other bodies, and is 
rejected. The steps may be illustrate- by the following 
equations : 

1. 2H,S0, + = CO, + 2H,S03. 

2. H^SOg + heat = H,0 + SO,. 

3. SO,, cold, + H,0 =: H,S03. 

The strength of the acid is 6. 4 per cent sulphurous acid 
gas, SO,. The solution of sodium carbonate absorbs the 
excess of SO, which the water will not absorb : ]sra2C03 + 
SO, = Na3S03 + CO,, liberating more carbonic acid gas. 

Properties. — This solution of sulphur dioxide is a color- 
less liquid of a sp. gr. not less than 1.035, strongly acid 
reaction, and an odor resembling burning sulphur. When 
heated it completely volatilizes. Its bleaching properties 
are pronounced, and depend upon the SO, which it 
contains. 

It is rarely used internally, its salts being preferred. 
Dose, from 3 to 30 minims (0.185 to 1.85 cc.) or more, with 
water. 

Its chief property is anti-parasitic, destroying microscopic 
organisms, for which reason it may be employed when an 
anti-ferment is desired. Its employment to prevent fer- 
mentation is manifold, that to check fermentation of cider 
at a certain stage being very extensive. 



134 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Nitric Acid. 

The acid next in importance to sulphuric acid is proba- 
bly nitric acid, HNO3, a combination of the highest oxide 
of nitrogen, N^O^, with water. It may be looked upon as 
consisting of 2HNO3 = H^O -\- N^O^. l^itrous acid con- 
tains in two molecules the same amount of water united 
with the next lower, or nitrous, oxide, li^fl^ — 2HNO2 = 

Preparation. — Nitric acid is made on a large scale by 
acting with sulphuric acid on either sodium or potassium 
nitrate contained in a retort, heating carefully to distilla- 
tion and collecting the distillate in well-cooled receivers. 
Equal weights of the acid, and nitrate in case of the 
potassium salt, are usually employed, but in some processes 
on a large scale more of the nitrate and less of the acid are 
preferably employed. 

These two reactions may be illustrated by equations, and 
are a means of illustrating 

The Functions and Uses of Equations. 

An equation tells not only what will be produced when 
two bodies capable of uniting chemically are brought in 
contact, but it tells also how much by weight of each body 
must be employed, or, on the other hand, how much by 
weight of each of the resulting compounds will be formed, 
or how much of each of the reacting bodies must be used 
to produce a certain weight of one or more of the resulting 
compounds. 

The first of these reactions is brought about when we 
take weights represented by one molecule of each, acid and 
salt, as follows: 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 135 

KNO3 + H,SO, = KHSO, + HNO3, 

and the second, when twice as much of the nitrate is em- 
ployed: 

2KNO3 + H,SO, = K,SO, + 2HNO3. 

In the first reaction one molecule of the nitrate is used 
and one molecule of nitric acid is produced, besides an 
acid sulphate of potassium, in which there is still some un- 
replaced hydrogen. In the second case two molecules of 
nitrate of potassium are used and two of nitric acid are 
produced, with the formation of a neutral sulphate of po- 
tassium as a by-product. The first process is employed 
when an exceedingly concentrated acid is not demanded; 
the acid sulphate, .too, is more easily removed from the 
retort than the neutral sulphate, which often forms a very 
hard cake. 

Now, to return to equations and their functions, we find 
that a symlol represents, among other things, the weight 
of the atom, or atomic lueight ; thus, K means, besides 
other things, that the potassium atom is 39 times heavier 
than the hydrogen atom. The formula of a compound 
represents, besides other things, the weight of the molecule 
— that is, the sum of its atomic weights; thus, KNO3 means 
that the weight of the molecule is 39 for K, + 14 for N, -|- 
48 for O3 — 101. In the same way we find that the mo- 
lecular weight of sulphuric acid is 98. Now, these figures 
denote the proportion in which the bodies'whose molecular 
weights they represent will unite with each other, accord- 
ing to the first equation : 

101 4- 98 = 136 + 63. 
KNO3 -f H,SO, = KHSO, + HNO3. 

That means if 101 of nitrate of potassium and 98 of acid 



136 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

be used, 136 of acid sulphate and 63 of nitric acid will be 
produced. 

The figures denote relative proportions by weight. They 
may mean grammes, ounces or pounds, or any other de- 
nomination of weight, but they must all represent one 
Icind of weight division. 

According to the second equation, different proportions 
of nitrate and acid would enter the reaction, as follows : 

202 + 98 = 174 + 126. 
2KNO3 + H,SO, = K,SO, + 2HNO3. 

In the chapter on chemical philosophy we learned that 
elements united with each other in definite chemical pro- 
portions, and that sometimes the proportion of one ele- 
ment is fixed, while the other increases in definite multiple 
proportions. Thus in CO and CO^ the C is fixed or con- 
stant, while the increased in the case of 00, in multiple 
proportion of 16 — namely, twice 16, etc. This is not true 
of elements alone, but of compounds as well. In the 
above two reactions the acid is constant, but the KNO3 
may be used in more than one proportion, subject to the 
law that it must be exactly a multiple proportion, and no 
more nor less than such multiple proportion expresses, the 
proportion being always understood to be taken by weight. 

So far we have learned that if we express the reactions 
between two or more bodies by equations, we can find out 
by employing the molecular weights of the bodies entering 
the change how much of each of those bodies must be em- 
ployed without causing a loss of either. 

We may now proceed a step further in our chemical 
mathematics. Writing an equation as we did above, we 
can tell from it how much of the bodies entering the reac- 



PHARMACEUTICAL AITD MEDICAL CHEMISTRY. 137 

tion must be used to produce a desired amount of the 
l^roduct. 

Thus, supposing it was our intention to make 100 pounds 
of nitric acid. From the above equation we know that in 
order to produce 63 pounds we must employ 101 pounds of 
the potassium salt and 98 pounds of sulphuric acid, pro- 
viding both were absolute — that is, 100 per cent. The 
proportions necessary for a given quantity may be calcu- 
lated by the rule of three thus: If 63 pounds metric acid 
require 101 pounds of nitrate, then 100 pounds would re- 
quire X quantity; or, as 63 is to 100, so must 101 be to the 
unknown quantity: 

63 : 100 :: 101 \ x. 

63)10100(160.31+ 

= number of pounds of the nitrate necessary to produce 
100 pounds nitric acid. 

63 : 100 :: 98 : a;. 

63)9800(155.55+ 

= number of pounds of sulphuric acid necessary to make 
100 pounds of nitric acid. 

When we say that, according to the equation, 98 pounds 
of sulphuric acid must be employed, we mean 100 per cent 
acid. If the acid were only 96 per cent absolute acid, we 
would need to employ of it more than 98 pounds. The 
weight of the 96 per cent acid to be employed would be 
ascertained in this wise, simply : 
96 per cent : 100 per cent :: 98 pounds : 102.2 pounds. 

Ansiver. — 102.2 pounds of the 96 per cent, sulphuric 
acid, therefore, contains the necessary 98 pounds of abso- 
lute acid. 

Properties of Nitric Acid. — This acid is, next to nitro 



138 PHAKMACEUTICAL AKD MEDICAL CHEMISTRY. 

hydrochloric, the most caustic of all acids. It is extremely 
corrosive, and has, a powerful oxidizing capacity, greater 
than any other body. It was made as early as the thir- 
teenth century, and was called aqua fortis by the ancients. 
It is now called nitric acid because made from nitrey the 
common name for potassium nitrate. Nitric acid is known 
also by the name azotic acid. 

By heat it is wholly volatilized; a residue would indicate 
presence of fixed impurities. It usually has a straw-yellow 
color, due to the presence of a lower acid of nitrogen, but 
when perfectly pure it is wholly colorless. Its action upon 
living tissue is that of a strong caustic ; it stains the skin 
an indelible yellow color, producing what some call xantho- 
proteic acid. The most characteristic property of nitric 
acid is its oxidizing powers; it oxidizes phosphorus, sul- 
phur, etc., and dissolves most of the metals; with salifiable 
bases it forms nitrates. It enters into the preparation of 
nitrohydrochloric acid, the only acid that will dissolve 
gold. In its action on many organic bodies its chemical 
affinity exerts itself with such violence as to produce very 
often enough heat to ignite the surrounding bodies. Its 
oxidizing properties depend on the evolution of nascent 
oxygen in its decomposition: 2HNO3 decomposes into 
H,0 + N,0, + 30. The specific gravity of the official 
acid is 1.414, corresponding to a strength of 68 per cent 
absolute acid; but the acid usually furnished by the manu- 
facturing chemist is seldom of that strength, being more 
often of a specific gravity of 1.35. Stress should always be 
laid on the importance of employing the 1.414 specific 
gravity acid in making the U. S. P. preparations, as that 
was used in the calculations for the preparations into which 
nitric acid enters. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 139 

Impurities in Nitric Acid. — All the impurities that may- 
be found in sulphuric acid may be looked for with the ap- 
propriate tests given under sulphuric acid. In addition, 
bromic and iodic acids may be present, which may have 
been in the nitrate as iodate and bromate. If the acid be 
diluted and shaken with a few drops of chloroform, the 
latter should not become colored — this would indicate the 
absence of iodine or bromine. The introduction of a small 
piece of pure zinc produces no color in the absence of iodic 
or bromic acids. 

Uses in Pharmacy and Medicine. — Nitric acid largely- 
diluted is the official dilute acid, which is given in doses of 
5 to 15 minims (0.30 to 0.90 cc.) as a tonic and astringent. 
In its undiluted form it is used as an escharotic for navus, 
warts, etc. 

Dilute Nitric Acid 

Has the same properties and uses as the strong, excepting 
those dependmg on greater concentration. It contains 10 
per cent of absolute acid. 

Hydrochloric Acid. 

In pharmaceutical nomenclature there is a certain spe- 
cific meaning implied by the titles occurring in the Phar- 
macopoeia, distinct altogether from the ordinary or usual 
meaning attached to those words. Thus the title " Acidum 
Hydrochloricum" or its English equivalent, ^^ Hydrochloric 
Acid," means the particular body described in the U. S. P. 
under this head, and no other. There are other kinds of 
hydrochloric acids, differing not in the essential of contain- 
ing the elements hydrogen and chlorine, but in strength, 
in the presence of impurities and contaminations, etc. 



140 PHARMACEUTICAL AN"D MEDICAL CHEMISTEY. 

The hydrochloric acid, therefore, that we are to consider 
is " a liquid composed of 31.9 per cent of absolute acid and 
68.1 per cent of water,'' as described in the Pharmacopoeia. 
It is at times called "muriatic acid," "'spirit of salt," 
"marine spirit," "marine acid," the latter terms referring 
to its source, common salt from the sea. 

Properties. — The pure acid is colorless; has a penetrat- 
ing, suffocating odor and extremely caustic taste, miscible 
with water and alcohol in all proportions. It has a specific 
gravity of 1.16, but may be concentrated to increase its 
density up to 1.22. Heat will completely volatilize it, and 
even at ordinary temperatures it slov/ly vaporizes, forming 
white fumes of ammonium chloride by combining with the 
ammonia in the air. This is a reliable test for either 
hydrochloric acid or ammonia; if a glass rod be dipped 
into ammonia water and held near the acid, the white 
fumes immediately appear. Ammonia, NH3 + HOI = am- 
monium chloride, NH^Cl. When very concentrated the 
acid blackens organic matter, as does sulphuric acid. The 
acid is not a liquid, but a gas, HCl, the only known 
combination of hydrogen and chlorine. When dissolved 
in water to the extent of 31.9 per cent, it constitutes the 
official acid. 

The acid and any of its salts form with solution of silver 
nitrate a characteristic white precipitate of chloride of 
silver, which is readily soluble in ammonia, but reprecipi- 
tated if the ammonia is again neutralized with an acid. 
Hydrochloric acid has strong chemical properties, com- 
bines with the alkalies and alkaloids to form salts, chlorides, 
and dissolves a number of the metals. 

Preparation. — If common salt, chloride of sodium, be 
mixed with sulphuric acid and the mixture distilled, hydro- 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 141 

chloric acid or the chloride of hydrogen will result. Un- 
less the salt and acid are pure the product will be con- 
taminated. On a large scale a very impure acid is obtained 
by the employment of common sulphuric acid and distilling 
from iron retorts. 

By far the greater part of the hydrochloric acid of the 
market is not made directly, but is a by-product in the 
manufacture of sodium sulphate in the process of convert- 
ing the chloride of sodium into carbonate and hydroxide, 
or into "soda-ash," as the mixture is called. Chloride of 
sodium is the source of most of the other sodium salts, 
which latter, however, cannot be made directly from the 
chloride. The chloride is first changed into the carbonate, 
from which most of the other sodium salts are then made 
with facility. To convert the chloride into the carbonate, 
Leblanc^s process is one means, and in the first stage of 
the process hydrochloric acid is a by-product : 

2]^aCl 4- H^SO, = 2HC1 + Na.SO,. 
Na.SO, + CaC03 + 30, = Na,003 + CaS -f 400. 

The salt NaOl reacts with the sulphuric acid and produces 
hydrochloric acid, which is in a gaseous condition, and is 
made to pass through towers, down which water trickles 
to dissolve the gas, and the acid then passes out as a 
relatively concentrated product. 

To produce a pure acid, pure fused chloride of sodium 
and pure sulphuric acid are employed, and the gas passed 
into distilled water contained in a series of bottles. The 
following reactions illustrate the chemistry of the process. 
Here, as in nitric acid, two proportions may be employed : 

58.5 98 120 36.5. 

NaOl 4- H,SO, = NaHSO, + HOI 



142 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

or, 

117 98 142 73 

2NaCl + H,SO, = Na,SO, + 2HC1; 

The figures denote the molecular proportions of NaCl 
and H2SO4 to be employed, as fully explained under sul- 
phuric acid. 

The first process yields acid sulphate of sodium, which 
is more easily removed from the retort than the neutral 
sulphate obtained in the first reaction. The acid sulphate 
may be further employed with more NaCl to yield HCl: 

NaHSO, + NaOl = Na.SO, + HCl. 

Converting the sulphuric acid first into the acid sulphate, 
and that into the normal or neutral, amounts to the same 
thing as does the second reaction above. 

Impurities. — As in nitric acid, so in hydrochloric acid 
may be present such impurities as are in the sulphuric acid 
from which it is made. The tests given under sulphuric 
acid may be here applied for these impurities. Additional 
impurities or contaminations may be chlorine and sulphuric 
acid. Chlorine will be recognized by liberating the iodine 
in a solution of iodide of potassium, the acid having pre- 
viously been diluted with five or six volumes of water. 
The iodine will be recognized by the familiar starch-test — 
that is, turning blue with starch-paste. If chloride of 
barium solution produces a precipitate when added to the 
dilute acid, the presence of sulphuric acid would be indi- 
cated. The following reactions illustrate the two tests just 
given: 

1. (a) 3KI + 01, = 2KC1 + I,; (b) I, + 10C.H„0. 
(starch) = 3(C,H,„0,),I, blue iodide of starch. 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 143 

2. BaCl, + H,SO, = 2H01 -f BaSO,, heavy white insolu- 
ble sulphate of barium. 

(It is doubted by many that iodide of starch is a definite 
chemical compound. The Pharmacopoeia of 1880 evidently 
did not recognize it as such, to judge from the name it gave 
to it — iodized starch.) 

The commercial acid is full of many kinds of impurities, 
the most injurious being" sulphurous acid, which is present 
sometimes to the extent of 10 per cent. The pharmacist 
should never sell it except for use in the arts. 

Uses of Hydrochloric Acid. — This acid is used primarily 
for the preparation of the dilute acid and the nitrohydro- 
chloric acid, but also largely as a medicine for its tonic, 
refrigerant and antiseptic properties. The dose is about 
five minims, largely diluted. In concentrated form it is a 
caustic, though not so powerful as nitric acid. It is fre- 
quently employed to dissolve alkaloids, iron and zinc in 
making the respective solutions of the Pharmacopoeia, 
and also aids in dissolving the arsenic in the ofiicial solu- 
tion of arsenous acid. With black oxide of manganese it 
yields the official chlorine-water, and by dissolving out the 
phosphate of calcium from animal charcoal it produces the 
purified animal charcoal. With cyanide of silver it gives 
diluted hydrocyanic acid. 

Antidote. — Hydrochloric acid is an irritant poison, pro- 
ducing a characteristic fiery redness of the tongue, black- 
ness of the lips and violent gastric pains. The best anti- 
dote is calcined magnesia made into a milk with water, 
given in copious draughts. Other mildly alkaline solutions, 
as soap, etc., are also efficient. Demulcent and bland 
drinks should follow. 



144 PHARMACEUTICAL AlS^D MEDICAL CHEMISTRY. 

Dilute Hydrochloric Acid. 

This acid has the same properties as the strong acid, 
from which it is made, excepting those depending on 
greater concentration. It contains 10 per cent of absolute 
acid, and has a specific gravity of 1.050. 

Nitrohydrochloric Acid. 

This acid, sometimes called '^nitromuriatic acid," "chlo- 
ronitric acid," " chloroazotic acid," ^' aqua regia,'' iitc, is 
made by mixing 18 parts of nitric acid with 82 parts of 
hydrochloric acid, in a capacious vessel, and allowing to 
stand until effervescence ceases. It is then directed to be 
poured into glass-stoppered bottles, which should not be 
more than half filled, and kept in a cool place. This acid 
was called aqua regia by the early chemists because of its 
property of dissolving gold, the king of the metals {regia 
from rex, which means king). There are various opinions 
regarding the nature of the reaction between strong nitric 
and hydrochloric acids, but the uitrosyl chloride theory 
seems to be shared by most authorities at present: HNOg 
+ 3HC1 = 2H,0 + NOCl + CI,. The presence of free 
chlorine gives, very probably, to the acid its power to dis- 
solve gold and other metals which have little affinity for 
oxygen. The nitrosyl chloride, ISTOCl, remains entirely in- 
active and unchanged during the solution of gold. 

Nitrohydrochloric acid is a golden-yellow, fuming, cor- 
rosive liquid, having a strong odor of chlorine; it liberates 
iodine from solutions of iodides. If kept exposed to sun- 
light it decomposes into hydrochloric acid, principally, and 
loses its chlorine. The pharmacist should never keep it in 
large quantity because of its proneness to decomposition 



PHARMACEUTICAL AI^D MEDICAL CHEMISTRY. 145 

and deterioration. Especial care should be observed not to 
transfer it to bottles before effervescence has entirely ceased, 
lest the pressure burst the bottles. 

Uses in Medicine. — Nitro-hydrochloric acid is employed 
in diseases of the liver, stimulating especially the flow of 
bile. It is used externally in very dilute solution as bath. 
The dose of the fresh acid is 3 to 5 drops, largely diluted. 

Dilute Nitro-hydrochloric Acid. 

Made as the above, with the addition of water when effer- 
vescence has entirely ceased ; the dilute nitric and hydro- 
chloric acids do not react, hence the employment of the 
strong acids and subsequent dilution with water. It is 
claimed by good authority that the water in the dilute acid 
causes a decomposition of the products formed by the reac- 
tion of nitric and hydrochloric, and a re-formation of the 
original acids, with a little nitrous acid as well. 

Clinical experience confirms the claim that dilute nitro- 
hydrochloric acid is not an eligible preparation. The 
strong acid is employed preferably, well diluted just before 
administration. 

Dilute Hydrobromic Acid. 

Properties. — Hydrobromic acid is a colorless, clear liquid, 
of a specific gravity of about 1.077, wholly volatile upon 
application of heat, odorless and of strongly acid taste and 
reaction. It contains 10 per cent by weight of absolute 
acid, corresponding in strength to most of the other dilute 
acids. There is no stronger acid official, but the market 
affords several that are more concentrated. 

Preparation. — The Pharmacopoeia does not give a process 



146 PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 

for the preparation of this acid, hut there are numerous 
methods in vogue for its production. The following yields 
a pure product: Sulphuric acid is made to react on an 
equal quantity of bromide of potassium in solution, and 
allowed to stand, to permit the sulphate of potassium, 
which is formed, to crystallize. The liquid is then poured 
off into a retort and distilled. The rationale of the process 
is this: 

2KBr + H,SO, = K,SO, + 3HBr, 

which, it will be seen, is the identical process employed in 
making hydrochloric acid, excepting that, in making the 
latter, distillation is resorted to at once. Another method, 
known as the " precipitation process,^' consists in reacting 
with tartaric acid upon potassium bromide, and allow- 
ing the acid tartrate of potassium, or cream of tartar, to 
crystallize : 

KBr + H,0,H,0, = KHC,H,0, + HBr. 

If the mixture is put away for several weeks in a place 
removed from dust and jarring, nearly all the cream of 
tartar will crystallize out, leaving the HBr in the liquid. 

The addition of a little alcohol facilitates the separation 
of the acid tartrate. This is known as Wade's Buchanan's 
method. FothergilVs acid is made after Wade's method, 
but it is somewhat weaker in strength. The acids made 
by these methods are open to the objection of containing 
small quantities of cream of tartar in solution. 

Among the many other methods only one more need be 
mentioned here, that of GoebeFs Glover's process, which 
consists in treating barium bromide, BaBr,, with sulphuric 



I 



I 



PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 147 

acid, producing HBr and the insoluble barium sulphate as 
precipitate : 

BaBr, + H,SO, = BaSO, + 2HBr. 

The first of these methods, known as Squibb's process, 
has the advantage over the others of producing a product 
of greater purity and more definite strength. 

Tests of Identity. — Solution of silver nitrate produces 
a yellowish-white precipitate, which is insoluble in nitric 
acid and very sparingly soluble in ammonia. 

If chlorine or nitric acid be added to the acid, bromine 
will be liberated, which is soluble in chloroform or disul- 
phide of carbon, giving to these liquids a yellow color. 

The chlorine has a greater affinity than the bromine has 
for the hydrogen in the HBr, and it therefore removes the 
bromine to take its place: 2HBr + 01, = 2HC1 + Br,. 

Nitric acid, when it liberates the bromine, probably does 
so in this wise : 

2HNO3 + 6HBr = 4H,0 + N,0, + 3Br,. 

Impurities. — Upon keeping for any length of time the 
acid sometimes becomes yellow; this is due to the libera- 
tion of bromine. It should not be used unless wholly 
colorless. 

Sulphuric acid may be present; if so, it may be detected 
by BaClj, which gives an insoluble white precipitate. 

Uses. — Dilute hydrobromic acid is employed medicinally 
for the same purposes that bromide of potassium and 
bromide of sodium are used. It is claimed to have advan- 
tages over the alkali bromides, as potassium and sodium 
are said to exert a depressing influence upon the system. 
The dose is up to 2 fluid drams (7.39 cc.) given in syrup or 
water. 



148 PHARMACEUTICAL Ai^D MEDICAL CHEMISTRY. 

Hydriodic Acid. 

The third of the halogen acids, hydriodic acid, is official 
in the form of a syrup of 1 per cent strength by weight. 
This preparation was introduced in the U. S. P. of 1880, 
and its introduction grew out of the difficulty of keeping 
hydriodic acid in aqueous solution, the iodine always be- 
coming liberated, in a short time rendering the preparation 
unfit for administration. Experiments have shown that 
syrup will efficiently preserve the acid. There is about 
1.30 gramme acid in 100 cc. syrup. 

Preparation. — Several methods may be employed in the 
preparation of syrup of hydriodic acid, and each involves a 
chemical process. One method is as follows: Ten parts of 
iodine are dissolved with gentle heat (extreme heat would 
produce loss of alcohol by evaporation and of iodine by 
vaporization) in 80 parts of alcohol. When dissolved the 
solution is added to 150 parts syrup and 150 parts of water, 
and a current of hydrosulphuric acid gas is passed through 
the mixture until it acquires a yellowish color and ceases to 
assume a brown tinge on shaking. The liquid is then fil- 
tered and evaporated during constant stirring at a temper- 
ature not exceeding 131° F., until all odor of hydrosul- 
phuric acid gas has disappeared. When cold it is flavored 
with spirit of orange 5 parts, and 500 parts of sugar added 
and enough water to make 1000 parts (all "parts by 
weight "). It is preserved in small, well-stoppered bottles 
and kept in a cool and dark place. The chemistry of the 
process is: I, + H,S = 2HI + S. The H,S may be gen- 
erated from iron sulphide and sulphuric acid : FeS -|- 
H^SO, = FeSO, + H,S. The FeS is contained in a flask 
with a double-perforated cork, through which pass a 



PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 149 

funnel to the bottom, to convey the acid, and a delivery 
tube, to carry away the gas. The gas is usually washed by 
being passed through water before it is conducted into 
the iodine solution. The sulphur which precipitates dur- 
ing the process remains behind on the filter. H^S is 
soluble to a certain extent in water, from which it can be 
expelled again by heat, hence that direction in the process. 

Properties. — Syrup of hydriodic acid is a transparent 
liquid, sometimes colorless, but usually of a pale-straw color, 
of a specific gravity of 1,313 and containing 1 per cent of 
absolute acid. 

If the substances used in its preparation are pure, as 
they should be, it will contain no impurities, but the 
U. S. P. gives tests for free iodine, chloride and sulphate. 

Free iodine will be recognized by the blue color with 
starch-paste. Chlorides or hydrochloric acid, with silver 
nitrate give precipitates which are soluble in ammonia. 
The precipitate with a bromide and silver nitrate is spar- 
ingly soluble in ammonia. 

Sulphuric acid is detected by BaCl^. 

Uses. — This preparation is possessed of the chemical 
properties peculiar to iodides in general. Its dose is from 
15 to 40 minims, considerably diluted. 

Phosphoric Acids. 

Preparation. — Phosphoric acid, as the official phos- 
phoric acid is termed by chemists, is never made by the 
pharmacist. By the manufacturing chemist it is made by 
carefully dissolving phosphorus in dilute nitric acid on a 
water bath. Dilute nitric acid exerts no action upon phos- 
phorus in the cold, but at an elevated temperature it changes 
it into phosphorous or phosphoric acid, according to its 



150 PHARMACEUTICAL AN"D MEDICAL CHEMISTEY. 

strength, which must be regulated accordingly. The 
stronger the nitric acid the more rapidly will it oxidize 
the phosphorus into phosphoric acid, but with the strong 
acid the reaction is so violent that the acid is always 
diluted with water for the operation. Serious accidents 
have happened from explosions resulting from the use of 
strong acid. The following equations will serve to demon- 
strate the reactions of nitric acid with phosphorus : 

First, when the nitric acid is well diluted : 

2P + 2HNO3 + 2H,0 = 2H3PO3 + N,0,; phosphorous 
acid is produced. This reaction may be resolved thus: 

The HNO3, when it oxidizes, as has been mentioned, 
resolves itself into: 

2HNO3 = H,0 + 1^,0, + 30; the oxygen attacks the 
phosphorus, 2P + 30 = P2O3, forming the phosphoroti,9 
oxide, which with water produces the phosphorous acid : 

P,0, + 3H,0 = 2H,P0,. 

Second, when the nitric acid is less dilute: 
6P + IOHNO3 + 4H,0 = 5N,0, + 6H3PO,, forming 
phosphoric acid. The several steps in this reaction are as 
in the preceding, excepting that more nitric acid, relatively, 
is employed, and consequently more oxygen is set free to 
produce the higher form of oxidation. 

IOHNO3 = 5H,0 + 5N,0, + 150; the oxygen again at- 
tacks the phosphorus: 6P + 150 = SP^O^, producing phos- 
phoric oxide, which with water gives phosphor^c acid. 

3P,0, + 9H,0=6H3PO,. 

The acid last described is official in the U. S. Pharma- 
copoeia. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 151 

Varieties of Phosphoric Acids. — Orthophosphoric anhy- 
dride, or anhydrous phosphoric acid, P^O^. 

Metaphosphoric acid, or glacial phosphoric acid, HPO3. 

Orthophosphoric acid, HgPO^. 

Diphosphoric acid or pyrophosphoric acid, H^P^O,. 

Besides these there are, among others of less importance, 
the following : 

Anhydrous phosphorous acid, P2O3. 

Phosphorous acid, H3PO3. 

Hypophosphorous acid, HgPO^. 

The PjOg is formed when phosphorus is burned in ex- 
cess of oxygen, and is in form of a white flocculent powder. 
With one molecule of water it gives met a-i^hosi^horic acid, 
and with 3 molecules of water or^/^ophosphoric acid. 

P.O. P,0, 

+ H,0 + 3H,0 



2HP0, .2H,P0 



By adding one molecule of water to one of metaphos- 
phoric acid the orthophosphoric will be formed : HPO3 -f- 
H^O = H3PO4. This may be made practically by boiling 
HPO3 with water. 

If, on the other hand, orthophosphoric acid be heated to 
drive off one molecule of water, the metaphosphoric will 
be produced : 

H3PO, 
-H,0 



HPO, 



The ortho-acid may be looked upon as a trihydrate, 
P,0, + 3H,0 (2H3POJ, while the meta-acid is a mono- 
hydrate P,0, + H,0 (2HPO3). 



152 PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 

Intermediate between the ortho and meta acids is an- 
other, the pyrophosphoric acid, H^P^O,. 

Theoretically this may be looked upon as consisting of 
one molecule of orthophosphoric and one of metaphosphoric 
acids : 

H3PO, 
+ HPO, 



HPO 



or, as being derived from two molecules of orthophosphoric 
acid by the abstraction of one molecule of water : 

H.P,0, (2H,P0.) 
-H,0 



The meta- is easily distinguished from the orthoacid 
by its property of coagulating albumen and precipitating 
with soluble salts of silver and barium, which properties 
are not possessed by the orthophosphoric acid. The latter 
gives a precipitate with silver nitrate in an excess of an 
alkaline solution only, which precipitate is yelloiu, and 
different from the precipitate formed by jo^/rophosphoric 
acid under like conditions, which is white. The pyro- 
phosphoric acid will not coagulate albumen, wherein it also 
differs from metaphosphoric acid. 

Meta means beyond, ortho straight, and -pyro fire. The 
pyro-acid is so termed because it is usually made by heat- 
ing the orthophosphoric acid. Heated to a much higher 
temperature, the pyrophosphoric acid is converted into 
the meta-acid, and the latter, by boiling in water, is recon- 
verted into the orthophosphoric. 

According to the foregoing explanation these three acids 



t 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 153 

are convertible into each other by the addition or abstrac- 
tion of water. The salts which these acids produce through 
the replacement of their hydrogen by metals have the 
corresponding names: 

Metaphosphoric acid, HPO3, gives metaphosphates: 
NaPOg, sodium metaphosphate. 

Orthophosphoric acid, H3PO4, gives phosphates: 
NagPO^, sodium phosphate. 

Pyrophosphoric acid, H^P^O,, gives pyrophosphates: 
Na^PjO^, sodium pyrophosphate. 

The Pharmacopoeia recognizes orthophosphoric acid 
under phosphoric acid and dilute phosphoric, while the 
pyrophosphoric acid is represented by pyrophosphate of 
sodium, Na^P^O^, and by pyrophosphate of iron,Fe4(P20,)3. 
(The latter is insoluble, but the U. S. P. salt is in form 
of soluble scales, made so by the addition of citrate of 
sodium.) 

These acids are all derivatives of the phosphoric oxide, 
P^Og, and have respectively one, three and four replaceable 
hydrogen atoms. 

Varieties of Phosphorous Acids. — The phosphoro?^5 oxide, 
P^Og, yields, as above stated, phosphorous acid, by the 
addition of water : 

+ 3H,0 



2H,P0, 



This acid forms phosph^Ye5 with bases. It has only two 
replaceable hydrogen atoms, and is sometimes written 
H^HPOg, to show that there are only two replaceable 
hydrogen atoms. Sodium phosphite would be written 



Na.HPOg. 



154 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

The oxide corresponding to %;oophosphorous acid, 
H3PO2, is not known ; it would be P^O. 

Hypophosphoroiis acid has only one replaceable hydrogen 
atom, and should be written HPH^Oj. 

It is represented in the Pharmacopoeia by sodium, po- 
tassium, calcium and iron hypophosphites. Their respective 
formula are NaPH,0„ KPH,0„ Oa(PH,OJ, and Fe^ 
(PH,OJ, 

(The student is advised to become thoroughly ac- 
quainted with the chemistry of phosphorus and its acids; as 
set forth in the foregoing chapter. He will find it neces- 
sary to have frequent recourse to it in his practice and 
studies.) 

Properties of Phosphoric Acid. — Phosphoric acid is a 
clear, colorless, syrupy liquid of strongly acid taste and re- 
action, containing 85 per cent of absolute acid and 15 per 
cent water. It is odorless, is miscible with water, and has 
a specific gravity of 1.710 at 15° 0. 

Impurities and Tests. — Occasionally small quantities of 
metaphosphoric acid, phosphates of calcium and mag- 
nesium, arsenic, sodium, potassium; hydrochloric, nitric, 
phosphorous and sulphuric acids, and more than 15 per 
cent of water are found. Phosphate of sodium has at 
times been detected in large quantities. 

To detect calcium and magnesium, the acid is super- 
saturated with ammonia- water; a precipitate indicates 
presence of the bases. 

Arsenic, lead and other metals are precipitated by pass- 
ing sulphuretted hydrogen through the acid for half an 
hour. A yellow precipitate indicates arsenic. 

Sodium or potassium may be detected by precipitating 
with acetate of lead (producing insoluble phosphate of 



\ 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 155' 

lead and soluble acetate of sodium and potassium), filter- 
ing and evaporating the solution to dryness. The residue 
will impart a yellow color to the colorless flame of a 
Bunsen-burner (sodium), and a purple flame if viewed 
through blue glass (potassium). 

Hydrochloric, nitric and sulphuric acids may Be looked 
for by the tests given before. 

Phosphorous acid, if present, decolorizes solution of 
permanganate of potassium. 

The Physiological Action^ of Phosphoric Acid is 
that of a powerful stimulant to the brain and nerves. Au- 
thorities differ as to its medicinal value. There is prob- 
ably some truth in the assertion of J. A. Thompson, that 
the complete oxidation of phosphorus impairs, or even de- 
stroys, its therapeutic properties. 

Dilute Phosphoric Acid. 

This contains 10 per cent of orthophosphoric acid, and 
all that has been said concerning phosphoric acid is ap- 
plicable to the dilute form. 

Glacial Phosphoric Acid. 

This acid is not made directly from phosphorus, but 
from calcined bones, by digesting them with suphuric acid. 
The insoluble sulphate of calcium which is produced is 
removed by filtration, the filtrate neutralized with am- 
monia, separated from the precipitated phosphates and 
evaporated to dryness. The residue, composed of phos- 
phate of ammonium, is then heated until all ammonia is 

driven off: 

(NH.),PO, 
— 3NH. 



H3PO, 



156 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

The orthophosphoric acid, HgPO^, upon continued ap- 
plication of heat parts with 1 molecule of water to form 
the dry fused glacial acid, which is the metaphosphoric acid : 

H3PO, 
— H„0 



HPO, 



Properties. — Griacial phosphoric acid is in transparent, 
colorless, glass-like masses, or in the form of sticks, obtained 
by fusing and pouring into moulds. 

It deliquesces on exposure to the air, dissolves in water 
and alcohol; the solutions having a strongly acid taste and 
reaction. It is never chemically pure, always containing 
sodium or other bases, which latter, however, are neces- 
sary to the formation of a solid acid. The chemically pure 
acid is a soft, gum-like mass. 

Impurities. — The impurities likely to occur in glacial 
phosphoric acid are those occurring in phosphoric acid. 
For the detection of these the same tests may be employed. 

Arsenous Acid. 

The substance described in the Pharmacopoeia under this 
title is not an acid, all acids, as before stated, requiring 
hydrogen in the base. The term is a conventional one: it 
ought to be arsenous oxide, which better expresses its 
chemical composition. This oxide becomes an acid (like 
SO3, CO,, P2O5, etc.) when combined with water: 

ASjOg + SH^O = 2H3AsOg, arsenous acid. 

There is another oxide of arsenic, a higher one, As^Og, 
which with water produces arsenic acid : 

AsO, + 3H,0 = 2H3ASO,. 



PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 157 

Arsenic acid is usually made by oxidizing arsenous oxide 
with nitric acid: 

3As,03 + 7H,0 + 4HNO3 = 6H3ASO, + 2N,0,. 

Preparation. — The arsenous acid is the only one of im- 
portance to the pharmacist. It is obtained in nature from 
arsenical ores by roasting in furnaces and conducting the 
hot vapors to surfaces on which they may cool and con- 
dense, usually cast-iron vessels with conical heads. Ar- 
senic is easily volatilized, taking up oxygen from the air as 
soon as it enters the gaseous condition, forming As^Og, 
which condenses into a sublimate. 

Properties. — It is a heavy crystalline or amorphous pow- 
der, or crystalline masses, semi-transparent, with streaked 
appearance. Soluble in from 30 to 80 or 90 parts of 
water, its solubility varying probably with the nature of its 
structure. In alcohol it is very little soluble, but hydro- 
chloric acid facilitates its solution, as do also the alkalies. 
Arsenous acid is permanent at ordinary temperatures, but 
when heated it volatilizes unchanged, emitting a garlicky 
odor, especially when reduced on ignited charcoal. Chem- 
ically, arsenous acid responds to all the tests for arsenic. 
The latter will be given in the chapter on Arsenic Salts. 

Poisonous Properties of Arsenous Acid. — See Arsenic 
Salts. 

Antidotes to Arsenous Acid. — There are two antidotes 
recognized by the U.S. Pharmacopoeia: (1) the freshly pre-, 
cipitated hydroxide of iron, obtained by adding water of 
ammonia to solution of tersulphate of iron, pouring pre- 
cipitate upon muslin strainer, draining and washing with 
water to remove any excess of ammonia or iron; (2) hydrated 
oxide of iron with magnesia, prepared by mixing calcined 



158 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

magnesia with solution of tersulphate of iron. (See chapter 
on Arsenic Salts for equations.) Until the antidote can be 
obtained, the poison should be removed as far as possible by 
inducing vomiting by means of the finger or a feather, or 
by administering a prompt emetic of mustard, salt and 
warm water, or 20 grains of powdered ipecac. Demulcent 
drinks, such as milk, flour and water, or white of egg and 
water, envelop the poison and retard its solution. 

Uses of Arsenous Acid. — It is employed usually as an al- 
terative in doses of -^q- to gV grain. 

Chromic Acid. 

This is really an oxide of chromium, and resembles 
in point of faulty nomenclature the acid previously de- 
scribed. Crystals of the acid readily separate from a mix- 
ture of a concentrated solution of potassium bichromate 
and strong sulphuric acid. The acid should be added to 
the bichromate solution slowly and with constant stirring, 
to prevent undue heating. The crystals, after removal of 
the mother-liquor, are washed with nitric acid, allowed to 
drain, and preserved in small well-stoppered bottles. This 
equation illustrates the reaction : 

K,Cr,0, -h 2H,S0, = 2Cr03 + 2KHS0, -f H,0. 

The acid sulphate of potassium remains in solution. 

Properties. — Chromic acid is in form of small crimson 
needles or columnar crystals, very deliquescent, and hence 
easily soluble in water. It attacks the skin, producing a 
caustic effect, wherefore it should always be handled with 
caution. It is best to use a glass spatula in manipulating 
it. Owing to the fact that it contains a large proportion 



PHARMACEUTICAL AN'D MEDICAL CHEMISTRY. 159 

of oxygen it readily attacks and oxidizes a good many 
bodies, causing combustion or explosion. Glycerin, sweet 
spirit of nitre and strong alcohol are among the easily oxid- 
izable bodies to which chromic oxide should not be added. 

Uses. — Chromic acid is never used internally. It is val- 
uable as an antiseptic and powerful caustic, and is used 
largely to remove warts and callous growths. 



160 PHAEMACEUTICAL AND MEDICAL CHEMISTKY. 



The Metals. 

Physical Properties. — There is a wide range in the densi- 
ties of the metals — lithium^ sodium and potassium being 
the three which are ligliter than water, while osmium is the 
heaviest, with iridium, platinum and gold following. The 
metals have all, more or less, a metallic lustre, their sur- 
faces admitting of being highly polished. In color they 
range from the white of silver to the red of copper and 
yellow of gold. Bismuth is white, but has a faint pinkish 
hue. 

Certain of the metals are malleable, a property which 
permits of their being extended by hammering or rolling. 
Gold is the most malleable of all the metals. Gold leaf is 
one of its attenuated forms. 

Ductility is a property involving the principle of tenacity, 
or power of resisting tension, possessed by metals which 
admit of being drawn out into wire. 

Volatility is probably possessed by all metals, but suffi- 
ciently high temperatures cannot be obtained to volatilize 
all. Mercury easily volatilizes at low temperature, but the 
highest degree of heat that we can to-day obtain only fuses 
or melts many of the metals. 

Chemical Properties. — Besides the combinations before 
referred to, into which metals enter — i.e., with the non- 
metals, forming oxides and salts — they combine with other 
metals. The compounds formed by the union of metals 
among themselves are called alloys, excepting that when 
one of the metals is mercury, the union is called an amal- 
gam. It is not positively known whether the metals in 
alloys combine chemically or not. One of tlie chief char- 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 161 

acteristics of the chemical force is its property of totally 
changing the physical appearances and properties of the 
bodies acted upon. This is not observed in case of alloys : 
the physical properties are still those of metals, and there 
is no such obliteration of the identity of the constituents 
as ensues when a metal combines with, e.g., oxygen or sul- 
phur, but on the other hand, the evolution of much heat in 
the formation of some alloys, notably those of potassium 
and sodium, would indicate that there is chemical action. 
The alterations of character are usually in hardness, melt- 
ing-point, color, tenacity and specific gravity. The com- 
bination, if it is such, takes place when the metals are 
melted together. While some chemists prefer to look upon 
alloys as chemical combinations, yet admitting that the 
chemical force exerted is very feeble, others consider them 
mere mechanical mixtures or solutions of one metal in the 
other in the liquid state. 

Some of the commoner alloys are: 
Brass, consisting of copper and zinc; 
Gun-metal, consisting of copper and tin; 
Bronze, consisting of copper, zinc and tin; 
German silver, consisting of copper, zinc and nickel; 
Pewter or Britannia, consisting of copper, tin and antimony; 
Shot, consisting of lead, with antimony or arsenic; 
Gold coin, consisting of gold, copper and sometimes silver. 

Cavities in teeth are usually filled with alloys specially 
prepared. 

The process of amalgamation is often resorted to in the 
extraction of some of the metals. Gold, which principally 
occurs in the metallic state as gold dust, is obtained from 
auriferous sand by treatment with mercury. The amalgam 
formed is heated in a retort, whereby the mercury is re- 



162 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

covered by distillation, the gold remaining as a residue in 
tlie retort. Silver is obtained from its poorer ores Dy tne 
same method. 

Unions of the Metals with the Halogens — Haloid Salts. — 
Chlorides. — Chlorine combines with metals to form chlo- 
rides. The combinations take place in proportions deter- 
mined by the atomicity of the metal, and the compounds 
formed may be looked upon as being derived from as many 
molecules of hydrochloric acid as the metal has bonds, by 
the replacement of the equivalent of hydrogen by a metal. 
This may be more easily comprehended by assuming hydro- 
chloric acid to be the type of all chlorides. 

HCl with potassium yields KCl, K replacing H; 

2HC1 with calcium yields CaCl^, Ca replacing 2H; 

3HC1 with gold yields AuClg, Au replacing 3H; 

Chlorides may be made in any of the following ways: 1. 
By acting on metals (antimony, copper, etc.) with element- 
ary chlorine; or, 2, with hydrochloric acid (zinc, iron, 
etc.) 3. By acting on oxides (silver) with free chlorine ; 
or, 4, with hydrochloric acid; and, 5, by dissolving carbon- 
ates or hydroxides in hydrochloric acid. 

Oxychlorides and Sulphochlorides are unions of 
chlorides with oxides and sulphides, respectively. Bismuth 
oxychloride may be viewed as being the chloride, BiClg, 
with two of the chlorine atoms replaced by oxygen, BiOCl. 
Metallic chlorides combine in definite proportions with 
ammonia and organic bases. Diammonium-platinous 
chloride, 2NH3.PtCl2, is such a compound, and is used 
occasionally in testing. Nearly all the chlorides are solu- 
ble. Notable exceptions are those of silver, lead " and 
mercurous mercury. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 163 

Bromides. — Bromine combines with most of the metals, 
and produces compounds analogous in composition to the 
chlorides, which they resemble in most of their properties. 
Chlorine having stronger affinity for metals than bromine^ 
replaces the latter in salts, setting it free. Strong sul- 
phuric acid also liberates bromine from any bromide. 

Iodides. — Unions of iodine with the metals are called 
iodides. They are analogous in properties to the chlorides 
and bromides. Chlorine and strong sulphuric acid will 
liberate the iodine, which turns blue with starch paste. 

Cyanides are combinations closely related to the haloid 
salts, excepting that the radical is composed of two ele- 
ments, carbon and nitrogen, together called cyanogen and 
written CN or Cy. Some cyanides are made by heating 
the metal in cyanogen gas or vaporized hydrocyanic acid. 
Cyanogen has its source chiefly in nitrogenous organic 
compounds, and a number of cyanides are made by heating 
the fixed alkalies with such bodies. A number of the 
cyanides unite with each other, producing the double 
cycmides. Ferricyanide and ferrocyanide of potassium are 
such double salts. K^FeCyg is the union of FeCy^ and 
4KCy — ferrocyanide potassium. These double cyanides 
are important in analysis. 

Oxygen Salts. — With oxygen the haloid salts produce a 
different class of salts, better known as belonging- to the 
oxygen salts; the haloid salts, it should be noticed, contain 
no oxygen. The oxygen salts may be derived from the 
corresponding acid by replacing the hydrogen with a metal 
— potassium in this case: 
(Potassium chloride, KCl, from HCl, hydrochloric acid.) 
Potassium chlorite, KCIO^, from HCIO^, chlorous acid. 
Potassium chlorate, KClOg, from HCIO3, chloric acid, 



164 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Iodine and bromine have corresponding salts, also 
obtained by replacing the hydrogen in corresponding acids. 
The names of the salts end as above. 

In a previous chapter it was explained that oxides are 
conveniently divided into three classes, — viz., acid, neutral 
and basic, — and that the first and third are capable of unit- 
ing to form salts, but that in the majority of cases, ^netallic 
salts are obtained from acids by replacing their hydrogen 
by a metal, basic or neutral oxide or hydro oxide. It was 
also explained that acids are unions of acid oxides with 
water, the oxide of hydrogen, and hence are intermediate 
compounds between oxides and oxygen salts. 

Another method of making salts is the interchange of 
the bases contained in soluble salts; sodium carbonate and 
barium nitrate will produce the insoluble carbonate of 
barium, which is precipitated, and soluble sodium nitrate, 
which remains in solution : 

Ba(N03), + Na,003 = BaC03 + 2NaN03. 

Insoluble salts containing halogen elements may also be 
made by this interchange method : 

HgCl, + 2KI = Hgl, + 2KC1. 

The mercuric chloride is decomposed, with the formation 
of insoluble mercuric iodide and soluble potassium chloride. 
All haloid salts and acids may therefore be looked upon as 
constructed after one type, hydrochloric acid being usually 
taken for the type, H — CI. By replacing the chlorine with 
any of the other halogen elements the remaining halogen 
acids may be obtained, and by replacing the hydrogen in 
these all the various haloid salts are produced. The hy- 
drogen of the acid or the metal in the salt is the base and 
the halogen element the radical. Now, oxygen salts may 



PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 165 

be regarded, as above stated, as compounds of acid oxides 
with basic oxides, or as analogous in composition to hydro- 
chloric acid; that is, as being constructed after the hydro- 
chloric acid type, containing a base and a radical, without 
reference to oxides. Thus the oxygen salts, sodium nitrate, 
NaNOg, and calcium carbonate, OaCOg, may be looked 
upon as constructed from HCl, the Na and Ca taking the 
place of hydrogen, and the g7'0ups of elements NO3 and 
OO3 the place of the chlorine. The NO3 and CO3 together 
as one radical discharge functions similar to those of chlo- 
rine, and like that element are capable of migrating un- 
changed and together from one compound to another. 

It is a subject of discussion among chemists which of 
these views is the correct one. The former is a rational 
view and the latter a more convenient one. The latter is 
also known as the binary theory of salts. 

Chemists agree that it is impossible to construct formulas 
capable of representing the exact arrangement of atoms in 
molecules; it is sufficient to be able to exhibit the combin- 
ing power of the atoms of the several elements in compounds 
and the manner in which any group of atoms splits up into 
smaller subordinate groups under the influence of other 
compounds. To illustrate this sulphuric acid is a good 
example, as it splits up or decomposes in four ways, accord- 
ing to the reagent used: 1. With zinc it splits up into H^ 
and SO4, the H^ becoming liberated and the SO^ combining 
with zinc to form its sulphate: Zn -f H^SO^ = ZnSO^ + H^. 
2. If lime, CaO, is added to sulphuric acid, it decomposes 
the latter into H2O and SO3, the H^O becoming free and 
the SO3 uniting with the OaO to form calcium sulphate: 
CaO + H,SO, = H,0 + CaSO,. 3. Sulphuretted hydrogen 
is formed when sulphide of iron, FeS, is added to sulphuric 



166 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

acid; H^SO^ in this case decomposes into H^S and 0^. 
H^SO, + FeS = H,S + FeSO,. 4. With barium dioxide, 
BaO^, sulphuric acid splits up into H^O^ and SO^; H^SO^ + 
BaO, = H,0, + BaSO,. 

Normal, Acid and Double Salts. — Monobasic acids pro- 
duce oiormal salts, by the replacement of their hydrogen by 
a metal. The metal may take the place of the hydrogen in 
one, two or three molecules of hydrochloric acid, for 
instance: 

HCl + K =.KC1 + H; 

2HC1 + Zn = ZnCl, + 2H; 

3HC1 + As =. ASCI3 + 3H. 

A normal salt is therefore one derived from an acid by 
replacing all the hydrogen in it by a metal: OaCOg, BaSO^. 

Acids which are hihasic or dibasic — that is, which have 
two replaceable hydrogen atoms — may produce two kinds 
of salts, normal and acid salts. The normal, as in case of 
salts derived from monobasic acids, have an equivalent of 
the metal in place of all the hydrogen, while the acid salt 
still contains some hydrogen, only part of it having been 
replaced in the acid by a metal: 

H^SO, + Na =: NaHSO,, acid sulphate of sodium, + H; 
H2SO4 -\- Na^ = Na^SO^, normal sulphate of sodium, + H^. 

An acid salt, therefore, is a salt containing a metal and 
hydrogen in its base (NaH)(003), (KH)(C,H,OJ. 

If the hydrogen in a dibasic or tribasic acid be replaced 
loy two metals a double salt results: Eochelle salt, double 
tartrate of sodium and potassium, KNaO^H^Og, is derived 
from tartaric acid, H^C^H^Og, by replacing one of its hy- 
drogen atoms with potassium, the other with sodium. 

Bibasic acids may therefore produce normal or neutral 



PHARMACEtJTICAL AKD MEDICAL CHEMISTRY. 167 

salts, as they are sometimes called, acid or Msalls, and 
double salts. 

Tribasic acids may produce as many kinds of salts as the 
bi basic, and in addition tertiary salts, having three metals 
in the base. 

Basic Salts or Oxysalts. — Normal salts give rise to two 
other classes of salts, the basic salts or oxysalts, and anhydro 
salts. The composition of these will be better understood 
by looking upon salts again as compounds of acid oxides 
with basic oxides, as stated above. (The terms basic oxide 
and basic salt should not be confounded by the student.) 

Normal sodium sulphate, ISTa^SO^, equals Na^O and SO3; 
Normal bismuth carbonate, 613(003)3, equals Bi^Og and 

300,; 
Normal ferric sulphate, Fe2(S0j3, equals Fe^Og and SSOg. 

In these it will be seen that there are as many acid oxide 
molecules as there are oxygen atoms in the basic oxide. 
When the proportion of the acid oxide is less, the salt is 
termed a basic salt : 

Basic bismuth carbonate, Bifi{QO^^, is Bi^Og and 200^; 
Basic bismuth carbonate, Bi^O^OOg, is Bi203 and 00^; 
Basic ferric sulphate, Fe^O^SO^, is Fe203 and SO3; 
Basic ferric sulphate, Fe20(SOj2^ is Fe203 and 2SO3. 

It will be noticed that the acid oxides are less in number 
than the number of atoms of oxygen in the basic oxide. 
There is an analogy of these basic oxysalts with the oxy- 
chlorides, oxybromides, etc.: thus the basic bismuth chlo- 
ride has the formula BiOOl or Bi^O^Ol^, the group of ele- 
ments CO3 in the basic carbonate acting as the single ele- 
ment does in the basic chloride. Some normal salts absorb 
moisture from the air; the moisture being water, H^O, there 



168 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

is consequently a greater proportion of base present than 
of acid, and a basic salt results: dFeSO^ + 0^ — Fe2(SOj3, 
normal ferric sulphate, and Fe^O^SO^, basic ferric sulphate. 
The FeSO^ is a ferrous salt and by the absorption of oxygen 
becomes oxidized to the ferric salt. 

The second class of salts of the normal kind are those 
which contain an excess, not of the basic oxide, as in the 
above, but of the acid oxide. Thus: 

Sodium anhydrosulphate, Na^S^O,, is Na^O and 2SO3; 
Potassium anhydrochromate, K^Or^O,, is K^O and 20r03. 

There are two acid oxides to one basic oxide in each of 
these salts. They are sometimes called acid salts because of 
the excess of acid oxide, and sometimes hi salts for the same 
reason, and because in the above cases they have two mole- 
cules of the acid oxides to designate. The prefix anhydro 
should designate, when added to the name of a normal salt, 
an addition to the latter of a molecule of the anhydrous acid. 
By anhydrous acid is meant that which is left after all the 
hydrogen and enough oxygen to form water have been re- 
moved from an acid; the anhydride of sulphuric acid is 
SO3: H,SO, = H,0 + SO3. SO3 added to Na.SO, gives 
Na,S0,S03, or Na,S,0,. So Cr03, added to K,CrO„ gives 
the so-called bichromate of potassium, K^Cr^O^. 

Kinds of Formulas. — Formulas are usually collections of 
symbols employed to express the compositio7i of compounds. 
The simplest is the empirical formula, which expresses 
merely the proportiofis of elements in compounds. Ben- 
zene, CgHg, contains six molecules of hydrogen and as many 
of carbon; hence its empirical formula is CH. 

A Molecular Formula expresses, in addition to this 
numerical relation, the actual number of atoms in a mole- 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 169 

cule. CgHg is the molecular formula of benzene, NaCl for 
common salt, chloride of sodium, etc. 

A Ratioi^al Formula shows at a glance the disposition 
of the compound toward reagents or other compounds hav- 
ing chemical afl&nity. The rational formula for sulphuric 
acid is H^SO^, which is to show that the H^ or the SO^ may 
be replaced; of hypophosphorous acid H(PH302), meaning 
that only one hydrogen atom may be replaced, and that the 
(PH^OJ together form a group which behaves chemically 
as a single element would. H3PO2 would not be a rational 
formula for hypophosphorous acid. 

A Graphic Formula indicates the equivalent or com- 
bining values of atoms, and the manner in which these are 
satisfied by combination. This is done by arranging the 
symbols in diagrams in such a way that each atom is con- 
nected with others by a number of lines or bonds cor- 
responding to its atomicity or degree of equivalence, a 
monad having one bond; a diad, two; a triad, three, etc. 
For example : 
Sulphurous acid, H^SOg. Sulphuric acid, H^SO^ 

Here the S has four bonds, In this the S has six 
H one and two. bonds. 

Calcium carbonate, Calcium phosphate, 

CaCOg. Oa3(POJ,. 

Ca<^\p_^ 



Ca<; ^C = Ca<5 



Ca< 



0-7P = 



■0/ 

Ca has two, carbon four Ca has two, two, 

and oxygen two bonds. and P five bonds. 



170 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

Graphic formulae are also called structural or constitu- 
tional. They do not represent the actual arrangement of 
the atoms in the molecule; chemists are ignorant of how 
atoms are arranged, and if they knew they could not rep- 
resent the arrangement on a plane surface. It will be seen 
from the above diagrams that each atom has its bonds satis- 
fied by union with a bond belonging to some other atom. 
The radical of a salt or acid is often spoken of as an unsat- 
urated group of elements. The SO^ is the sulphuric radical 
and has two free bonds, whose places in sulphuric acid are 
occupied by hydrogen : 

The two free bonds may be saturated with two atoms of 
a monad metal, or with one atom of diad metal. The (SO J 
acts as an element with two bonds would. 

In the same way the nitric radical (NO3) performs all the 
functions of a single atom with one bond: 

^0 

In writing graphic formulas for salt containing oxygen, 
the water type is usually employed. H^O = H — — H, the 
left hydrogen in case of salts being replaced by metals, and 
the right by a single element or a group of elements. The 
number of bonds which the base has determines the num- 
ber of molecules of water to be taken. 

Sulphuric acid has two bonds in the base, H^, hence the 
graphic formula must be constructed after two molecules 
of water: 



► 



PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 171 

H— 0— H H— 0— Q^O 

H— 0— H H— 0—10=0 

It will be seen that the two right-hand hydrogen atoms 
are replaced by SO^. 

Written after the hydrochloric-acid type, water is derived 
from HCl by replacing the CI with OH, and, vice versa, the 
HOI from H,0 by replacing the OH with 01. 

The student is urged to read again the opening lessons 
under the Mineral Acids, to which the above is supple- 
mental. 



172 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 



The Alkalies. 

IisT the beginning of the course the student learned that 
the elements are divided, for convenience of study, into 
divisions and subdivisions, and that the two primary divi- 
sions represent metals and non-metals respectively. All 
of the important non-metals have now been studied indi- 
vidually and in their important combinations with each 
other. The acids, the last subject of study, may be 
looked upon as belonging to the latter — i.e., to combina- 
tions containing only non-metals, if hydrogen is con- 
sidered a non-metal, which is disputed by some on the 
seemingly valid ground that in its chemical behavior it 
resembles the metals more closely than the non-metals. 
The student will now go furthur and confine his attention 
to the metals and their combinations with the non-metals, 
which combinations are termed salts. Salts are usually 
unions of metals with some combination of non-metals, 
the combination usually, 7iot always, being an acid. An 
acid may be viewed, therefore, in the additional sense of 
being a prepared condition of one or more non-metals for 
combining with a metal or metals. (See introductory 
chapter to the study of the Inorganic Acids.) 

The first convenient subdivision of the metals is the 
alkalies, or alkali metals — sodium, potassium, lithium, 
caesium and rubidium. The latter two are of no importance 
to the pharmacist. The hypothetical ammonium is usually 
included in this division. 

They are called alkalies because they were formerly, 
and still are, to an extent, obtained from the ashes of a 
plant called glassivort (which ashes yielded not only soda 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 173 

and potassa, but which were also employed in the manufac- 
ture of glass). The name of the ashes in Arabic is gali; in 
French and Spanish, call. The Arabic prefix al is equiv- 
alent to our English article the. The Arabic word galaj 
signifies " to roast in a pan/^ and originated probably from 
the manner in which the ashes were collected. Soda and 
potassa were obtained by a process of lixiviation — i.e., by 
treating the ashes with water, which dissolved out both sub- 
stances and yielded them up again upon evaporation. This 
was the original method of obtaining soda and potassa. 

Properties. — The alkali metals resemble each other in 
many of their physical properties. There is one dissimi- 
larity, however, that is marked. Sodium, potassium and 
lithium and their salts are fixed, whereas ammonium and 
its salts are volatile. This distinction is brought to mind 
by the terms " fixed alkalies " for the former and " volatile 
alkali " for the latter. Fixed means remaining permanent 
upon the application of heat, and volatile, dissipating or 
entering the gaseous state in contact with heat. In com- 
position there is also a difference between the fixed alkalies 
and the volatile alkali; each of the former consist of a 
single element, K, ISTa, and Li, while the latter is compound, 
consisting of the two elements hydrogen and nitrogen, 
NH^, but the NH^ is purely hypothetical, and used for con- 
venience — NH3 is the base. This may not be a distinction; 
that which is termed ammonium we have succeeded in 
decomposing into the two elements hydrogen and nitrogen, 
while sodium, potassium and lithium have resisted up to 
the present all attempts at further subdivision, and hence 
are called elements. 

The bodies which we now call elements may be com- 
pounds whose constituents have more chemism or chemi- 



174 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

cal affinity for each other than for other bodies. It may 
be that there are bodies which, if our elements or some of 
them are compounds, have greater affinity for one or the 
other of the constituents, but if there are, they have never 
been brought in contact or condition to exert their greater 
power of chemical affinity. Whenever the latter happens 
a new element or elements will be discovered. The annals 
of chemical history verify this^ as now and then a body 
which had been supposed to be simple is found to be com- 
pound. 

The alkaline hydroxides resemble each other in the fol- 
lowing common properties: .They (1) turn red litmus- 
paper blue, and (2) colorless phenol-phthalein solution to 
a fuchsine red, (3) neutralize acids, (4) form salts with 
acids, which are neutral or acid according to the propor- 
tion of the acid, and sometimes alkaline; (5) saponify fats 
— that is, form soap with fatty bodies, and (6) cauterize 
the skin. The metals of the alkalies are all soft (easily 
cut with a knife), all lighter than water, fuse very readily 
at low temperatures and volatilize* at high temperatures, 
decompose water with the evolution of hydrogen, combine 
with great energy with oxygen, forming strongly basic 
oxides, which dissolve easily in water, producing alkaline 
hydroxides, which are powerfully caustic : 

K, or Na, -f 2H,0 = 2K0H or 2NaOH + H,. 

Sodium Hydroxide. 

2K, + 0, = 2K,0. K,0 + H,0 = 2K0H. 

Potassium oxide. 
(Basic.) 

They all form alums and produce basic oxides with 
oxygen — that is, they will unite with acids to make salts 
in which they will act as hase. Acid oxides, such as SO,, 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 175 

P^Oj, OO2, etc., constitute the acid portion of a salt; thus, 
sulphite of sodium, Na^SO,, is composed of: 

The base K^O, and 

The radical or acid. SO2 

Making the salt K^SOg 

Attention is again directed to the synonomy of the 
terms base and basylous radical, and radical and acidulous 
radical. In the above salt the K^O may be termed sim- 
ply the base or the basylous radical, and the SO^ the 
radical or the acidulous radical. The latter form of 
nomenclature assumes that a salt is composed of two 
radicals or roots, one a base and the other an acid. The 
former mode is preferable for its brevity — i.e., base and 
radical. The metals of the alkalies form only one chloride 
each, their salts are all colorless and soluble; and all but 
ammonium give characteristic colors to colorless flames. 
Sodium colors the Bunsen-burner flame intensely yellow, 
potassium gives it a distinct purple hue if viewed through 
blue glass, and lithium produces a bright crimson color. 
Caesium means blue, and rubidium, red. 

Alums. 

It is a peculiar fact that all the metals of the alkalies 
form alums, double salts of great interest. 

An alum may be defined to be a double salt formed 
by the union of the sulphate of an alkali metal with the 
sulphate of a pseudo-triad, and having 24 molecules of 
water of crystallization. 

For illustration: Potassa-alum has the formula K^Al^- 
(SOJ424H2O, which shows that theoretically it is com- 
posed of : 



176 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Potassium sulphate KjSO^ 

Aluminum sulphate (pseudo-triad) K2A12(S0J3 



K,A1,(S0,). 

In crystallizing it takes up 24 molecules of water. 

The following alums may be resolved as the potassa 
alum: 

Iron alum, K2re2(S0j424H20, containing potassium. 

Iron alum, (NHj2Fe2(SO^)424H20, containing ammo- 
nium. 

Chrome alum, {NHJ,Cr,(S0J,2.'<H,0. 

Caesium alum, Cs,Al,(SOJ,24H,0, etc. 

Iron, chromium, aluminum, and other metals which have 
four bonds, of which only three are active, may be called 
pseudo-triads, for want of a better term. The proportions 
in which they unite with other elements and the formulas 
obtained for some of their salts in ultimate analysis tend 
to show that they have in some cases three active bonds, 
but never in the case of single atoms; hvo atoms always 
have together six bonds. 

OrapMc formula serve to illustrate this ; for instance : 

Ferric chloride, Fe^Clg, not FeClg, may have its atoms 
arranged in this manner: 

/CI 
^ef-Cl 
\C1 

/CI 
Fe^Cl 

A1==0 



Aluminum oxide, Al^Oj. 



:0 



A1 = 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 177 

The atoms of iron and aluminum have each four bonds, 
but two bonds, one from each atom, neutralize or combines 
each other, so to speak, so that two atoms together have six 
bonds. It will not be inappropriate, therefore, to call these 
metals false or pseud o- triads. (Eecent investigations made 
with aluminum make it doubtful whether it is a pseudo- 
triad. The vapor density of some of its combinations would 
seem to indicate that it is a true triad.) The alkali metals 
have each only one bond and are probably the only monad 
metals entering into the composition of the alums. 

Ammonium is only a hypothetical metal, and is classed 
with the alkali metals because of the similarity it has in its 
chemical behavior to the metals of that group. 

Potassium Salts. 

The salts of potassium are very numerous, and are among 
the most important salts used in pharmacy. They are color- 
less when crystallized, and white when powdered or granu- 
lated. Excepting the bitartrate, sulphate and chlorate, 
they are very soluble in water; those mentioned are soluble 
to a less extent. Owing to their extreme solubility there 
is no good test in which precipitation may be employed as 
a means of determining their presence or identity. The 
greater number of the salts of potassium are insoluble in 
alcohol. 

Sources. — Formerly the product obtained by lixiviating 
wood-ashes was the only source, but to-day the chief sources 
are the products of the Stassfurt mines in Germany, which 
consist of a variety of potassium salts, among which the 
chloride predominates. The salts are converted into sul- 
phate and this into carbonate, from which most of the 
pharmacopoeial salts are made. 



178 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Argols is the chief source of cream of tartar, bitartrate 
of potassium. This salt exists naturally in the juice of 
grapes, but deposits upon the sides of the casks when fer- 
mentation sets in, which changes the sugar into alcohol, 
and precipitates the salts, which are (as mentioned above) 
insoluble in alcohol. 

Suint, or the soapy or fatty substance obtained from 
sheep's wool, yields a number of potassium salts, which are 
obtained by washing the wool, filtering the washings, con- 
centrating and crystallizing. 

Some potassium salts are obtained in the extraction of 
sugar from beet-roots. The mother-liquor left after the 
third or fourth crystallization of sugar, and from which no 
more crystals can be obtained, and which constitutes beet- 
root molasses, contains enough potassium salts to make it 
profitable to extract them." 

Calcutta nitre, nitrate of potassium, is also found in Nat- 
ure. See below. 

Tests for Potassium Salts. — The colorless, flame of the 
Bunsen-burner is colored violet or purple, best seen through 
blue glass. 

When a strong solution of a potassium salt is added to 
excess of a concentrated solution of tartaric acid, a white 
crystalline precipitate slowly forms. The precipitation 
may be hastened by the addition of alcohol; the precipitate 
is cream of tartar, which is the least soluble of the potas- 
sium salts. 

The addition of a solution of platinic chloride containing 
a little alcohol and hydrochloric acid produces in strong 
solutions of potassium salts a yellow precipitate consisting 
of the double chloride of potassium and platinum, PtCl^ + 
2K01. 



PHARMACEUTICAL AIsTD MEDICAL CHEMISTRY. 179 

In the collective study of the potassium salts it is best to 
begin with the natural products and follow the preparation 
of these into the various pharmacopoeial salts. The alpha- 
betical arrangement of the U. S. P. is best for classifica- 
tion; in studying the formation of these salts it is simpler 
to follow their derivation. 

Impurities. — By noting the impurities in the sources it 
will not be difficult to remember the possible impurities in 
the various salts, as it rarely happens that contamination 
takes place during their preparation. The chief impurities 
in the several sources which may be looked for . in the 
various salts by the respective tests are : 

Chlorides. — Precipitated by AglS'Og. 

Sulphates. — Precipitated by solution BaOl^. 

OARBOi^ATES. — In some, effervescence with acids. 

Alkaline Earths. — The neutralized solution of a salt 
gives cloudiness or white precipitate with solution Na^OO^. 

Organic Impurities. — Strong sulphuric acid will be- 
come blackened if fragments of a salt containing organic 
matter are sprinkled upon its surface. 

Silica. — In the presence of silica a solution acidulated 
with nitric acid and evaporated to dryness yields a residue 
which is not wholly soluble in water. 

Metals. — A solution of a salt acidulated with nitric 
acid gives a black color or precipitate with sulphuretted 
hydrogen or ammonium sulphide in the presence of metals. 

The foregoing are general impurities; specific contam- 
inations will receive mention in appropriate places. 

Potassium Carbonate. PotassH Carbonas. KfiO^. — From 
this salt is obtained or prepared the majority of the phar- 
macopoeial preparations of potassium. 

Potassium carbonate is obtained from the products of 



180 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

the Stassfurt mines by a process of conversion, or from 
wood-ashes by repeated crystallizations. It is a white crys- 
talline or granular powder, odorless and strongly alkaline, 
deliquescent, and, in large doses, caustic. Lemon juice or 
diluted vinegar is an appropriate antidote. Dose, 5 to 15 
grains (0.33 to 1.00 gm.). 

Potassium Bicarbonate. Potassii Bicarbonas. KHCO3. — Ob- 
tained by saturating a solution of carbonate of potassium 
with carbonic acid gas, evaporating at a low temperature 
(70" 0.) and crystallizing— e.g., K,C03 + H,0 + CO, = 
2KHCO3. I* occurs in transparent monoclinic prisms, 
permanent in dry air, odorless, of slightly alkaline reac- 
tion, decomposed by heat or boiling into carbonate and 
CO —e.g., 2KHCO3 = K,C03 + H,0 + CO,. This salt 
is usually quite pure, and is the starting-point in the manu- 
facture of a number of other salts. It is also valuable 
because of the large proportion of carbonic acid gas it can 
be made to yield. It is milder than the carbonate; chem- 
ically, it is an acid salt, because it contains hydrogen in the 
base. 

Potassium Sulphite. Potassii Sulphis. K^SOg. — If sulphur- 
ous acid gas is passed through solution of potassium car- 
bonate until all of the carbonic acid is expelled, potassium 
sulphite will be formed— e.g., K^COg + SO, = K^SOg -f CO,. 
A little sulphate is usually formed, but the U. S. P. of 1880 
required at least 90 per cent of sulphite. 

This salt is in white, opaque crystals, or in crystalline 
powder slightly deliquescent, odorless, and of a bitter, 
sulphurous taste. It is possessed of valuable anti- fermen- 
tative properties, retarding or checking various kinds of 
fermentation and destroying lower forms of organic life. 



PHAKMACEUTICAL AND MEDICAL CHEMISTRY. 181 

Dose ranges from 10 to 40 grains (0.66 to 2.66 gms.). 
Formula, K2SO3.2H2O. It is no longer official. 

Potassium Acetate. Potassii Acefas. KC^HgO^.— Made by 
neutralizing acetic acid with potassium bicarbonate. 
KHCO3 + H0,H30, = K0,H30, + H,0 + 00,. The 
solution is carefully evaporated in a porcelain dish, avoid- 
ing contact with iron (iron gives red color by forming the 
i-ed acetate of iron). This salt may be made from the car- 
bonate, but the bicarbonate should be preferred because of 
its greater purity. Organic matter may be present from 
the acetic acid, which is of organic origin. It is in white, 
foliaceous, satiny masses, or in white powder, very deli- 
quescent, should be odorless, but often has faint odor of 
acetic acid, neutral or faintly alkaline reaction ; soluble in 
alcohol. It is a diuretic. Dose, 1 to 4 gms. 

Potassium Citrate. Potassii Citras. Kfijifl^. — Made by 
adding crystals of citric acid to a solution of bicarbonate 
of potassium until neutralized or until effervescence ceases, 
evaporating and crystallizing : 3KHCO3 + Kfi^Ufi^ 
= Kfijlfi, + 3H,0 + 300,. It is a white granular 
powder, deliquescent, odorless, slightly alkaline taste, and 
neutral or faintly alkaline reaction. In addition to general 
impurities it may contain tartrate^ which is detected by 
adding acetic acid to a concentrated solution of the salt — 
in its presence a white crystalline precipitate of the acid 
tartrate will deposit. It is diaphoretic in doses of 0.66 to 
1.33 gms. 

Solution Potassium Citrate. Liquor Potassii Citratis. Made 
in a manner similar to that employed for the preparation of 
the salt, without evaporating the solution. It is a clear, 
colorless liquid, odorless, containing about 9 per cent of 



182 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

the salt, and should be prepared as needed. As refrigerant 
and diaphoretic, the dose is 3 to 5 cc. 

Mixture Botassium Citrate. — Neutral Mixture. — This 
mixture resembles the foregoing in all respects, excepting, 
perhaps, that the use of lemon juice in place of citric acid 
renders it more agreeable in taste. Properties and dose 
the same as those of the solution. This mixture has been 
dismissed from the 1890 U. S. P. 

Effervescent Potassium Citrate. Potassii Citras Effervescens. 
— This preparation has been added to the Pharmacopoeia 
in its last revision. Potassium bicarbonate and citric acid 
are intimately mixed in a warm mortar, and the resulting 
paste rapidly dried at or below 120° C, and then reduced 
to any desired degree of fineness by powdering. The bicar- 
bonate and the acid are incompatible, and in the presence 
of moisture or water reaction ensues, with the liberation of 
carbonic acid gas : 3KHCO3 + H3C,H,0, = K3C,H,0, 
+ SH^O + BCO^. The preparation should be kept pro- 
tected from dampness. 

Solution of Arsenite of Potassium. — Fowler's solution 
(see under Arsenic). 

Sulphurated Potassa. Potassa Sulphurata. — This prepara- 
tion is made by heating together carbonate of potassium 
and sublimed sulphur until the mixture is completely 
melted, pouring on a stone slab, and breaking into pieces 
when cooled. Liver of Sulphur is a name sometimes 
given to it. It is not a definite chemical compound, but 
consists of varying quantities of sulphide and hyposulphite 
of potassium. The TJ. S. P. requires the presence of at 
least 12.85 per cent of sulphur combined with potassium 
to form sulphide. The pieces are of a liver-brown to a 
brownish -yellow color, of a faint, disagreeable odor and 



h 



PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 183 

repulsive taste. Nearly wholly soluble in water, only 
partly in alcohol. Though sometimes given internally, it 
is usually employed externally in skin diseases. 

Potassium Hypophosphite. Potassii Hypophosphis. KH^PO,. 
— Made by acting on the potassium carbonate with calcium 
hypophosphite, filtering the solution, evaporating and granu- 
lating: K,C03 + Ca(H,PO,), = 2KH,P0, + Ca003. The 
salt occurs usually as a white granular powder, is very 
deliquescent, odorless, of sharp, bitter taste, soluble in al- 
cohol. The U. S. P. guards against the presence of phos- 
phate, by directing that not more than a slight cloudiness 
should appear on mixing an aqueous solution of the salt 
with test solution of magnesium. Potassium hypophos- 
phite is one of the ingredients of syrup of hypophosphites. 
Dose is from 5 to 15 grains (0.33 to 1.00 Gm.). 

Potassa. KOH. — Potassa is the starting-point in the 
manufacture of another series of the potassium salts. It 
is made by boiling together potassium carbonate, or, prefer- 
ably, the bicarbonate, and slaked lime, setting the mixture 
aside until clear and removing the clear solution by means 
of a glass syphon, and evaporating in a clean iron, or better, 
silver vessel until a fluid of an oily consistence is obtained. 
The hot caustic potassa is poured into moulds, producing 
the sticks of the market: Oa(OH), + 2KHCO3 = C!aC03 
+ 2K0H + H,0 + CO,. 

Potassa by Alcohol is potassa purified by dissolving in alco- 
hol — the alcohol dissolves only the potassa, leaving the 
impurities behind, which may be removed by filtration. 
Caustic potassa is in form of sticks usually, hard, very 
deliquescent, odorless or having a faint odor of lye, very 
caustic and strongly alkaline. It is principally used as a 
caustic. Antidotes are diluted vinegar, or citric acid solu- 



184 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

tion, or lemon juice, followed with a bland oil to correct its 
irritant effects. It should not be handled with the fingers. 
The commercial product contains from 20 to 40 per cent 
moisture. 

Solution of Potassa. Liquor PotasscB. — Made as the above 
without evaporating, or by dissolving caustic potassa in 
water. It is an aqueous solution containing about five per 
cent of KOH, clear, colorless, odorless, very acrid and 
caustic taste. All that has been said about potassa applies 
to the solution. It is given internally as an antacid in 
doses of 0.5 to 1.00 cc. diluted. 

Potassa with Lime. Potassa cum Calce. KOH and CaO. — 
Made by rubbing together equal weights of potassa and 
dry lime. This preparation is a grayish-white powder, 
very alkaline in appearance, and deliquescent. Sometimes 
it is found in sticks similar to the caustic potassa sticks. 
Used externally as caustic, but is milder and slower in its 
operation than potassa alone. 

Potassium Permanganate. Potassii Permanganas. K^Mn^Og 
or KMnO^. — Made by heating together caustic potassa, 
chlorate of potassium and dioxide of manganese, and boil- 
ing the resulting mass in water to change the formed 
manganate into the permanganate, which is obtained 
from the resulting solution by careful evaporation: (1) 
6K0H + 3MnO, -f- KCIO3 = 3K,MnO, (potassium manga- 
nate) -f KOI + 3H,0; (2) 3K,MnO, + 2H,0 = 2KMnO, 
(potassium permanganate) -j- MnO^ + 4K0II. The po- 
tassium hydroxide is usually neutralized with dilute H^SO^, 
because not all of the manganate is oxidized in presence of 
excess of potassa. The salt occurs as deep purple, violet 
or nearly black, needle-shaped prisms of a metallic lustre. 



PHARMACEUTICAL AFD MEDICAL CHEMISTRY. 185 

permanent, without odor, sweet, astringent taste, and is 
easily decomposed by alcohol. 

Permanganate of potassium is one of the most powerful 
of our oxidizing agents. The U. S. P. directs that " it 
should not be triturated nor combined in solution with 
organic or readily oxidizable substances.^' It parts easily 
with its oxygen, this combining with organic matter. 
Chemically it is used as a volumetric test and oxidizer, but 
its solution should not be kept too long, as light and air 
decompose it. It is an excellent disinfectant. 

Potassium Iodide. Potassii lodidum. KI. — This, the most 
important of the potassium salts, is prepared by adding a 
slight excess of iodine to an aqueous solution of potassa, 
evaporating to dryness and mixing the product with char- 
coal, which is then heated to dull redness. The resulting 
mass contains iodide of potassium, which may be dissolved 
out and purified by crystallization, e.g.: 6K0H -j- 31, 
= SKI H- KIO3 H- 3H,0. The charcoal removes the oxy- 
gen from the iodate (KIO3) : 2KIO3 + 30, = 2KI + 600. 
This salt is sometimes made from ferrous iodide (see 
process under Bromide). Iodide of potassium is in form 
of colorless, translucent cubical crystals, somewhat deli- 
quescent, peculiar faint odor, saline, bitter taste, soluble in 
18 parts alcohol. 

When pure it is neutral, but the product of the market 
has a slightly alkaline reaction. This is desirable, since 
a slight alkalinity prevents the separation of the iodine. 
ThelJ. S. P. allows the presence of 0.5 per cent of chloride 
or bromide. This iodide, like other soluble ones, precipi- 
tates alkaloids, hence is incompatible with these. It is of- 
ficial also in form of ointment. 

Potassium Bromide. Potassii Bromidum. KBr. — This salt is 



186 PHARMACEUTICAL AlfD MEDICAL CHEMISTRY. 

made by two methods. One is identical with that em- 
ployed in making the iodide, bromine being used in place 
of iodine. By substituting the symbol Br for I, the 
student will have the reactions for the process. The other 
method employs ferrous bromide and potassium carbonate. 
The ferrous bromide is made by acting on iron with bro- 
mine : Fe, + 2Br, = 2FeBr,; FeBr, + K^COg = FeC03 
+ 2KBr. The iron becomes an insoluble carbonate, and 
precipitates as such, while the KBr remains in solution, from 
which it is obtained in crystals on evaporating the solution. 
The fact that this salt was formerly imported, but is now 
made in this country on a scale large enough to supply the 
demands of other countries besides our own, is good evi- 
dence of the progress of chemical industry in this country. 
Bromide of potassium is in form of translucent cubical 
crystals, permanent, odorless, pungent saline taste and 
neutral reaction. The commercial product is usually in 
white opaque crystals, having a slightly alkaline reaction 
to prevent the liberation of bromine. The U. S. P. allows 
the presence of 3 per cent of chloride. The Pharmacopceia 
gives tests for the presence of bromate and iodide and the 
usual impurities. Bromide of potassium is a nervine; its 
dose is from 0.33 to 1.33 gms. 

Potassium Ferrocyanide. Potassii Ferrocyanidum. K^FeCy,. 
SH^O. — Yellow Prussiate of Potash. — Made by heating 
nitrogenous animal matter with crude potash, lixiviating 
the mass and treating with freshly-made ferrous carbonate 
and crystallizing. It occurs in large lemon-yellow trans- 
lucent prisms or tablets, somewhat effervescent in air, odor- 
less. Unlike most other salts containing cyanogen (CjS"), 
it is not poisonous when pure. It is recognized by the 
U. S. P., not for its medicinal properties, for it is seldom 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 187 

employed as a remedy, but for its reliabilily as a test for 
ferric salts, with whicli it gives a deep blue color and 
precipitate. 

Potassium Cyanide. Pofassii Cyanidum. KON. — By heating 
a mixture of potassium carbonate and ferrocyanide of iron 
to redness, potassium cyanide is obtained. Of the several 
qualities found in the market only the granular white 
variety should be employed medicinally. It is deliquescent, 
odorless, of a bitter-almond taste, strongly alkaline reac- 
tion and very poisonous. Its toxic action is the same as 
that of hydrocyanic acid. Dose is ^-^ to ^ grain (.004 to 
.008 gm.). 

Potassium Bichromate. Potassii Bichromas. K^Cr^O,. — 
Made by adding strong sulphuric acid to a solution of 
potassium chromate : 2K,OrO, + H^SO, == K,Cr,0,+K,SO, 
+ H^O. The difference in the solubility of the two salts 
affords a means of separating them by fractional crystal- 
lization. The salt is in form of large orange-red, four-sided 
prisms; permanent, odorless, metallic taste. It is used 
almost exclusively in form of test-solution. In large doses 
it is poisonous; chalk, magnesia or soap are appropriate 
antidotes. 

Potassium Chlorate. Potassii Chloras. KCIO3. — The salt is 
now made by reacting with calcium chlorate upon potas- 
sium chloride: Ca(0103), + 2K01 = OaOl, + 2KCIO3, and 
crystallizing. Occurs in colorless plates of a pearly lustre, 
permanent, odorless, characteristic saline taste, neutral re- 
action explosive. Great care should be observed in hand- 
ling potassium chlorate; it should not be triturated with 
bodies that are easily oxidized. The salt readily parts with 
its oxygen when brought into contact with bodies having 
an affinity for that element. If heated it loses its oxygen : 



188 PHARMACEUTICAL Al^B MEDICAL CHEMISTRY. 

2KCIO3 + heat = 2KC1 + 30,. This fact is taken advan- 
tage of in the preparation of oxygen for chemical and 
medicinal uses. Internally the salt is given in doses of 
from 0.20 to 0.66 gm. 

Troches of Potassium Chlorate each contain 5 grains of 
the salt. It should be noted that all of the foregoing salts 
are derivatives of potassium carbonates. 

Potassium Bitartrate. Potass/'/' B/'tarfras. KRCJIfl^, — 
Cream of tartar is obtained from grape- juice, in which it 
occurs naturally. Being insoluble in alcohol, it separates 
as soon as the sugar in the juice changes by fermentation 
into alcohol. The deposit thus formed on the interior of 
wine casks is known as argols, and when purified by 
passing its solution through animal charcoal and evapor- 
ating, constitutes cream of tartar. The salt is usually in 
form of white, gritty powder, odorless, of pleasant acid 
taste, and soluble in 210 parts of water, being the least 
soluble of the potassium salts. 

Calcium tartrate is also present in grape-juice, and the 
U. S. P. allows the presence of 6 per cent in cream of 
tartar. It is refrigerant in doses of 4 gms. Tartaric acid 
and most of the tartrates are made from it. Compound- 
jalap powder contains it as one of its ingredients. 

Potassium Tartrate. Potass/'/' Tartras, 1880. K^C^H^Og. — 
This salt is no longer official. It is made by reacting on 
cream of tartar with potassium carbonate: 2KHC^H^0, 
-f K,C03 = 2K,C,H,03 + H,0 + CO,. It occurs as white 
powder, somewhat deliquescent, odorless, saline, bitter 
taste; neutral reaction. In doses of 8 to 30 Gm. it is 
purgative. 

Potassium and Sodium Tartrate. Potass// et Sodii Tartras. 
KNaC^H^Og. — RocHELLE Salt. — The process for making 



PHARMACEUTICAL Al^B MEDICAL CHEMISTRY. 189 

this double salt is the same as that employed for making 
the neutral tartrate, excepting that sodium carbonate is used 
in place of potassium carbonate: 2KHC4H^Og -f Na^COg 
= 3KNaC,H,0, + H,0 + 00,. Eochelle salt is in form 
of white powder, becoming hard in moist air, odorless, 
mildly saline taste, neutral reaction. It is a purgative in 
doses of 15 to 30 Gm. Seidlitz powders contain it as one 
of their ingredients. 

This salt, which contains two metals in the base, is a 
good illustration of a double salt; it may be looked upon 
as being thus constituted: 2KNaO,H,0„ = K.O.H^, 
+ Na,0,Hp,. 

Potassium Nitrate. PotassH Nitras. KNO3. — Nitre or salt- 
petre, or Calcutta nitre, occurs as an efflorescence upon the 
soil in India, and is purified by repeated crystallization. 
The salt is iil form of colorless, transparent, six-sided 
prisms, or as a crystalline powder, permanent in the air, 
odorless, cooling, pungent taste, neutral reaction. It is 
diaphoretic and diuretic in doses of 0.66 Om. In the arts 
it is used largely in making gunpowder. The cheaper 
sodium nitrate is not suitable for this purpose on account 
of its deliquescence. The nitrate is also official in form of 
a paper, made by immersing unsized paper in a strong 
solution of the nitrate and drying. The product is the 
Charta Potassii Nitratis. 

Potassium Sulphate. Potassii Sulphas. K^SO^. — This salt 
is not made directly, but is a by-product in the manufacture 
of nitric acid from potassium nitrate and sulphuric acid — 
e.g.: 2KNO3 + H,SO, = K^SO, + 2HNO3. The HNO3 
distils over, leaving the potassium sulphate in the retort. 
Eepeated crystallization purifies the salt. It is in colorless, 
six-sided prisms, permanent, odorless, sharp saline taste. 



190 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

neutral reaction. It was formerly used as a vehicle or 
diluent in Dover's powder, but has been superseded by sugar 
of milk in the 1880 U. S. P. 

The carbonate, chromate, cyanide, dichromate, ferri- 
cyanide, ferrocyanide, hydroxide, iodide, sulphate and 
sulphocyanate of potassium are official in form of test- 
solutions. 

In the consideration of the potassium salts it has been 
thought best to follow the order of derivation, which 
necessitated the study of the several organic salts at the 
same time. The organic potassium salts are the acetate, 
bitartrate, tartrate, citrate and tartrate of sodium and 
potassium. 

Sodium Salts. 

The sodium salts resemble the potassium salts very closely 
in their physical and chemical behavior and properties 
and in the methods of their preparation. There are no two 
other metals that resemble each other more closely in their 
combinations than do sodium and potassium; nearly all 
that has been said of the potassium salts is equally true of 
the sodium combinations. The latter are somewhat more 
soluble, so that the tartrate test and the platinic chloride 
test are not applicable. The only test for sodium consists 
in its imparting a bright-yellow color to a colorless flame. 
The general impurities and tests are the same as in the 
potassium compounds. 

Sources. — The sodium chloride found in solution in 
brines and in the sea, and crystallized or in masses in mines, 
is the chief source of the sodium salts used in pharmacy. 
As with potassium, the carbonate is the salt from which 



PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 191 

most others are made — this salt being made from the chlo- 
ride by conversion. The processes employed for conversion 
are the LeUanc and the Solvay or Am?nonia processes. 
The Leblanc process was employed very largely before the 
Solvay process was introduced, but is rapidly falling into 
disuse. It consists in treating the chloride with sul- 
phuric acid and heating the resulting sodium sulphate 
with limestone, the combined action of which decomposes 
it to form sodium carbonate. The soluble sodium car- 
bonate is afterward obtained by washing the residue with 
water; e.g. : 

■2NaCl +H,SO, = Na.SO, -f 2HC1. 
Na^SO, -f 20a003 + 20 == Na,C03 +2CaO + CaS + 300,. 

The ISTa^OOg in crystallizing takes up 10 molecules of 
water and becomes the ''soda" of commerce. In the Sol- 
vay process strong solutions of sodium chloride are treated 
simultaneously with ammonia, NHg , and carbonic acid gas, 
OOj , yielding bicarbonate of sodium: NaOl + NHg + 00, 
+ H,0 = NaHOOg + NH.Ol. The solutions are concen- 
trated so that the bicarbonate precipitates and the ammo- 
nium chloride formed remains in solution. The dry am- 
monium chloride obtained by evaporating its solution is 
heated with lime, OaO, obtained in making the 00, for the 
process from OaOOg (OaOOg -|- heat = OaO + OOJ, and is in 
this way made to yield 2NH,01 + OaO = 2NH3 + OaOl, + 
11,0. This process is very economical, it being only neces- 
sary to employ ammonia once. It furnishes a comparatively 
pure bicarbonate of sodium. Other natural salts of sodium 
besides the chloride are the nitrate or Chili saltpetre, found 
as an efflorescence on the soil in Ohili, the borate or borax 
occurring crystallized and imbedded in the mud of lake 



192 PHARMACEUTICAL AN'D MEDICAL CHEMISTRY. 

bottoms in California, Tuscany, etc., or as solution in borax- 
springs, and the sulphate in solution in springs. The nitrate 
and borate are never converted into other salts of sodium; 
the sulphate when it occurs naturally is usually the chief 
ingredient of the so-called bitter loaters. 

Cryolite, a double fluoride of sodium and aluminum, 
6NaF.A],F,, or SNaF.AlFg, found abundantly in Green- 
land, furnishes a considerable quantity of the sodium 
bicarbonate of the market to-day. The ore is melted with 
lime, yielding solution of aluminate of sodium and insolu- 
ble calcium fluoride: GNaF.Al.F^ + 6CaO = 6CaF, + 
3Na,0. Al,03 , or Na^Al.O,. The solution of SNa^O.Al^Og 
is treated with 6C0, + 6H,0 and yields A1,(0H), + 
GNaHCOg. The aluminum hydroxide is insoluble, while 
the bicarbonate is removed with water. The bicarbonate 
thus produced is very pure. From the carbonate or 
bicarbonate of sodium all of the pharmacopoeial sodium 
salts are made, excepting the borate and nitrate, which 
occur naturally, and the chlorate, sulphate and hypo- 
sulphite. 

Sodium Carbonate. Sodii Carbonas. Na^COg.lOH^O. — Pre- 
pared, as above shown, by the Leblanc or Solvay pro- 
cesses. The latter process yields bicarbonate, which is 
converted into the carbonate by heating, to drive off part 
of the carbonic acid gas: SNaHCOg + heat = Na^COg + 
H^O -|- COj. The salt crystallizes with 10 molecules of 
water, which it loses again by exposure to the air, it being 
efflorescent. Its chief use in pharmacy is in the prepara- 
tion of other sodium salts, and in this application it is 
necessary to employ a salt containing the full amount of 
water of crystallization. The molecular weight of the salt 
when pure is 286, but if effloresced it is always stronger in 



PHARMA.CEUTICAL AND MEDICAL CHEMISTRY. 193 

actual carbonate; and this must be taken into account 
when converting it into other salts. 

Dried Sodium Carbonate. Sodii Carbonas Exsiccatus. — The 
water of crystallization is expelled by heat from the crys- 
tallized carbonate^, so that 200 parts are reduced to 100 
parts by weight. 

The U. S. P. requires the presence of 73 per cent, an- 
hydrous carbonate. 

Sodium Bicarbonate, Commercial. — Made by Solvay pro- 
cess, or by passing a stream of carbonic acid gas into the 
carbonate: Na.COg+CO, + H,0 = 2NaH003, e.g., not less 
than 95 per cent, of NaHCOg need be present, and not more 
than 5 per cent impurities. The U. S. P. 1880 required 
this salt to be of 95 per cent, strength. It is no longer 
official. 

Sodium Bicarbonate. Sodii Bicarbonas. NaHOOg. — By this 
title the U. S. P. designates a salt of 98.6 per cent, strength. 
It is made by removing the chloride, sulphate and car- 
bonate from the commercial salt by washing the latter with a 
small quantity of water, which dissolve out the very soluble 
impurities before it dissolves the bicarbonate, which is less 
soluble. 

It is also made by the Solvay process and from Cryolite, 
as shown above. This purified salt is devoid of the bitter 
taste of the commercial, because of the absence of carbonate 
and sulphate. 

Soda. — Caustic Soda. — Sodium Hydroxide, NaOH. If 
sodium carbonate is heated with lime, CaO, the lime re- 
moves the CO2 and leaves NaOH, sodium hydroxide, in 
solution, which, when evaporated to dryness and fused and 
poured into moulds, constitutes the stick form of caustic 
soda: Na,C034- CaO + H,0 = CaC03+ 2 NaOH. When ex- 



194 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

ceedingly pure caustic soda is required for analytical pur- 
poses, the metal sodium is oxidized, thus: Nag -j- = 
Ka^O; Na^O + H,0 = 2NaOH. 

Solution of Soda. Liquor Sodcs. — Made either directly from 
the carbonate and lime, without evaporating the solution, 
or by dissolving the stick soda in water to the extent of 5 
per cent. It is antacid, and resembles closely the Solution 
of Potassa. 

Sodium Arsenate. Sodii Arsenas. Na^HAsO^ + TH^O. — 
Prepared by fusing together sodium carbonate, sodium 
nitrate and arsenous acid, dissolving the fused mass in 
water and crystallizing: 

As,03 + 2NaN03 + Ka,003 + H,0 = 

2Na,HAsO, + ^fi, + CO,. 

This salt is sometimes preferred to arsenous acid ; its 
medical properties are the same. Dose, 0.0027 to 0.008 Gm. 

Sodium Bisulphite. Sodii Bisulphis. NaHSOg. — Sulphurous 
acid gas, SO^, is passed into solution of sodium carbonate 
to saturation, the solution evaporated and crystallized: 
Na,003 + H,0 + 2S0, = 2NaHS03 + CO,. The sulphite, 
when exposed to the air, becomes sulphate by absorbing 
oxygen, or carbonate by taking up 00,; it should therefore 
be kept in small bottles well filled. Its principal use is as 
an antiseptic. 

Sodium Sulphite. Sodii Sulphis. Na.SOg -f 7H,0.— The 
normal sodium sulphite is made by the same process as 
the bisulphite or acid sulphate, except that a greater quan- 
tity of SO, is employed: Na,C03 + SO, = Na,S03 + CO,. 
This salt is a very useful antiferment and antiseptic, and is 
usually preferred to the bisulphite. 

Sodium Bromide. Sodii Bromidum. NaBr. — Usually made 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 195 

by acting on ferrous bromide, FeBr^, with sodium carbonate, 
filtering, evaporating the solution and crystallizing or granu- 
lating: FeBr, + Na.COg == FeCO, + 2NaBr. The ferrous 
bromide is prepared by acting on iron with bromine. Bro- 
mide of sodium is similar in medicinal properties to potas- 
sium bromide. Its dose is from 0.50 to 2.00 Gms. 

Sodium Chloride. Sodii Chloridum. NaCL— As above stated, 
this salt is the source of most of the sodium salts. It is 
obtained from sea-water and from salt-wells by evaporation, 
or from salt-mines, and purified by repeated crystallization. 
It is used most largely as a condiment, and is an essential 
constituent of our food. The presence of calcium or mag- 
nesium chloride causes the granulated salt to cake. 

Sodium Hypophosphite. Sodii Hypopliosphis. NaH^POj + 
H^O. — Sodium carbonate is treated with calcium hypophos- 
phite, when double decomposition ensues, forming insoluble 
calcium carbonate and soluble sodium hypophosphite, 
which is obtained by carefully evaporating the solution 
and granulating: 1^2. fiO, + C!a(H,POJ, = 2]S'aH,P0, + 
CaOOg. The evaporation should be conducted at a very 
low heat to avoid explosion. Too much heat causes the 
disengagement of the inflammable gases, hydrogen and 
phosphoretted hydrogen. This salt is an ingredient in 
Syrup of Hypophosphites. 

When this salt is heated or triturated with nitrates, 
chlorates or other oxidizing agents it explodes violently; 
hence it must be handled with extreme care. 

Sodium Iodide. Sodii lodidum. Nal). — This salt is pre- 
pared as the bromide, using ferrous iodide : Fel^ -\- 
Na^OOj — FeCOg + 2NaI. Also made by adding iodine to 
solution of soda: 6NaOH + 31^ = smi -f NalOg -f 311^0. 
The iodate, NalOg, in reduced to the iodide with charcoal, 



196 PHARMACEUTICAL AKD MEDICAL CHEMISTEY. 

viz. : 2NaI03 + 30, = Na^I + 6C0. All that has been said 
about potassium iodide applies to this salt. 

Sodium Phosphate. Sodii Phosphas. ^ii^^VO^-^l^Rfi.— 
This is an acid salt made by displacing part of the calcium in 
acid calcium phosphate Avith sodium from sodium carbonate, 
e.g.: CaH,(POJ, + Na,C03 = OaHPO, + Na.HPO, + H,0 
+ COj. The CaHFO^ is insoluble and is separated by 
filtration. This salt contains over 60^ of water of crystal- 
lization. Used principally as a cathartic in doses of half an 
ounce, and in preparing the test-solution of sodium phos- 
phate. 

Sodium Pyrophosphate. Sodii Pyrophosphas. Na^P^O, + 
lOHj. — By removing 1 molecule of water from 2 molecules 
of the acid phosphate, by heat, the pyrophosphate is ob- 
tained: 2Na,HP0, + heat = Na^P^O, + H,0. It is em- 
ployed in the preparation of ferric pyrophosphate. 

Sodium Acetate. Sodii Acetas. NaO^HgO, + 3H,0.— Ob- 
tained by adding acetic acid to solution of sodium carbonate 
until effervescence ceases, evaporating and crystallizing or 
granulating. 2HC,H30, + Na,C03 = 2NaO,H30, + H,0 
-j- COj. As diuretic it is preferred by some to potassium 
acetate. 

Sodium Benzoate. Sodii Benzoas. NaC^H^O,. — Made as 
the above, using benzoic in place of acetic acid : Na2003+ 
2H0,H,0, = 2NaO,H,0, + H,0 -f- CO,. With ferric sul- 
phate this salt gives a flesh-colored precipitate. 

Sodium Salicylate. Sodii Sal icy I as. ^d^CJlfi^. — Made as 
the above, employing salicylic in place of benzoic acid: 
Na,C03 + 2HC,H,03 = 2NaC,H,03 + H,0 -\- CO,. This 
salt gives with ferric compounds an intense violet color. 

Sodium Sulphocarbolate. Sodii Su/phocarbo/as. NaS03Cg- 
H (OH) + 211,0. Socium Paraphenolsulphonate, Barium sul- 



PHARMACEUTICAL AND MEDICAL CHEMISTRY, 197 

phocarbolate is treated with sodium carbonate, forming 
barium carbonate, which precipitates, and sodium sulphocar- 
bolate, which remains in solution, from which it is obtained 
by crystallization. This salt is used as an antiferment and 
a disinfectant. 

Sodium Borate. Sodii Boras. Na,B,0, + lOH^O.— The 
source of borax has already been mentioned. It is sometimes 
made by fusing boric acid with dried sodium carbonate. A 
little added to alcohol containing sulphuric acid gives a 
green color to the flame of burning alcohol. Borax is mildly 
alkaline and diuretic. It is frequently used in solution 
to whiten ointments. See Boron. 

Sodium Nitrate. Sodii Nitras. NaNOg. — Chili nitre. Chili 
saltpetre. Found native on the soil of Chili and Peru. Puri- 
fied by repeated crystallization. Its chief use is in the 
manufacture of nitric acid. 

Sodium Sull)hate. Sodii Sulphas. ISTa^SO^ + lOH.O.— Ob- 
tained as an intermediate product in the manufacture of 
sodium carbonate by the Leblanc process, and as a by-product 
in manufacture of nitric and hydrochloric acids. G-lauber^s 
salt, as it is frequently termed, rapidly effloresces in dry 
air. It is used largely in veterinary practice as a cathartic. 

Sodium Chlorate. Sodii Chloras. NaClOg. — Made from 
potassium chlorate and sodium bitartrate: KCIO3 + 
NaHC.H.O, = NaC103+ KHC,H,0,. The cream of tartar 

4 4 6 3 I 4 4 6 

separates while the chlorate of sodium remains in solution 
and is obtained in crystals upon filtration and evaporation. 
It has an advantage over potassium chlorate in its greater 
solubility. It should not he triturated with easily oxidiz- 
ahle todies. Accidents have occured from its being rubbed 
with sulphur. 

Sodium Hyposulphite. Sodii Hyposulphis. ^\^fi^-\-bRfi. 



198 PHARMACEUTICAL A5^D MEDICAL CHEMISTRY. 

— The correct name for this salt is sodium thiosulphate. It 
is obtained by decomposing calcium thiosulphate with 
sodium sulphate : CaS,03 + Na^SO, = CaSO, + Na.S.Og. 
The solution when filtered and evaporated yields crystals 
of sodium thiosulphate. A solution of this salt constitutes 
the photographer^s ''hypo," which dissolves the unaltered 
bromide or chloride in the film. In pharmacy it is chiefly 
employed in volumetric analysis. 

Solution of Chlorinated Soda. Liquor Sodce Chlora . — La 
barraque's Solution. This bleaching solution is easily made- 
by adding to a solution of carbonate of sodium some chlorin- 
ated lime, allowing the carbonate of calcium formed to 
subside, and decanting the clear solution: 2Na2C03 -[- 
OaCl,Ca(C10), = 2Ca003 + 2NaCl + 2^001 It is used 
principally as a bleaching agent, and is usually substituted 
for javelle-water, which is made from potassium carbonate 
instead of sodium carbonate. It should contain at least 
2.6^ of available chlorine. 

Solution of Sodium Arsenate. Liquor Sodii Arsenatis. — A 
solution containing one per cent of sodium arsenate. 

Solution of Sodium Silicate. Liquor Sodii Si/icatis. — Made by 
fusing sand and sodium carbonate together, and dissolving 
the soluble portion of the mass thus obtained in water. It 
contains from 25 to 30 per cent, of silicate of sodium. Com- 
mercially it is known as soluble glass. It is employed in 
the preparation of some surgical dressings. 

Troches of Sodium Bicarbonate. Trochisci Sodii Bicarbonafis. 
— These contain each three grains of sodium bicarbonate. 
Mild antacid. 

Rhubarb and Soda Mixture. Mistura Rhei et Sodae. — Con- 
tains about 3.5 per cent, of sodium bicarbonate. 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 199 

Ammonium Salts. 

Much which the student has learned in the study of the 
potassium and sodium salts may be applied with profit 
in the study of the salts of ammonium. These salts are 
akin in many respects to those of potassium and sodium, 
especially in absence of color, solubility, physical and 
chemical properties and medicinal uses. The base am- 
monium is, however, of a compound nature, consisting of 
nitrogen and hydrogen, ~^B.^, while the salts of sodium 
and potassium have single elements as their bases. This, 
with the fact that ammonium salts are all volatile, marks 
the chief points of distinction between them. The student 
should be careful not to mistake ammonium, NH^, for am- 
monm, NH3. The former is a hypothetical base, which 
has not yet been obtained by itself, or isolated from any of 
its compounds, while the latter is a gas easily generated 
from any ammonium salt by heating with an alkali hy- 
droxide. We assume that ammonium has one free bond, 
and ammonia none, and that the nitrogen in the former 
has five bonds and in the latter only three : 

H .H 

% I / 

NH, : \n — free;NH3: N — H 

•^ H ^H 

NH4 is an unsaturated group of atoms having one 
free bond (the nitrogen having 5 bonds, of which 4 are 
satisfied with 4 hydrogen atoms), and does exist by itself, 
thus differing from NHg, which is completely saturated, 
and a stable though extremely volatile body. The latter, 
]SrH3, differs from sodium or potassium in uniting or com- 



200 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

bining with all of the elements of another body. The fol- 
lowing equations illustrate this difference: 

Na, + 2H,0 = 2NaOH + H,. 
NH3 + H,0 = NH^OH. 

The sodium, it will be observed, does not unite with all 
of the hydrogen in water; it sets one atom from each 
molecule free. Ammonia, on the contrary, enters into 
complete combination, the number of bonds of the nitrogen 
increasing from 3 to 5. 

Tests for Ammonium Salts. — 1. The presence of any 
ammonium salt may be easily detected by heating with 
caustic soda or potassa, or with any alkali hydroxide. The 
gas ammonia is given off, which may be recognized by its 
odor, or by its producing white fumes when brought in con- 
tact with the vapors of hydrochloric acid. For illustration : 

NH^Ol + NaOH = NH3 + H,0 + NaCl. 

2. NH3 + HCl = NH^Cl. 

3. Solutions of ammonium salts give yellow precipitates 
with solution of platinic chloride containing a little HOI. 

4. Heat volatilizes ammonium salts. 

5. Nessler's reagent gives red color with even minute 
quantities of ammonia. (See page 45.) 

Sources. — In one of the processes for the manufacture of 
illuminating gas, coal is subjected to destructive distilla- 
tion; the gas thus generated contains among other products 
considerable quantities of ammonia. This is removed from 
the illuminating gas in the process of washing, the water 
dissolving out the NH3 and retaining it in solution. From 
this solution, or ammoniacal gas liquor, as it is called, the 
ammonia is removed by treatment with either sulphuric 



PHAEMACEUTIOAL AKD MEDICAL CHEMISTRY. 201 

or hydrochloric acid, evaporating and purifying by sub- 
limation the sulphate or chloride thus formed : 

2 NH3 + H^SO, = (NHJ^SO,, or NH3 + HCl = NH^Cl. 

If sulphuric acid has been employed, the sulphate formed 
is coverted into the chloride by subliming with sodium 
chloride: 2Na01 + (NHJ.SO, = ISTa^SO, + 2NH,01. 

Ammonium Chloride. Ammonii ChloHdum. NH^Cl. — This 
is the starting-point in the manufacture of the ammonium 
salts ; from it all others are made, either directly or indi- 
rectly, through the sulphate or carbonate or hydroxide. 
The impurities found in this salt may be looked for in all 
the others. They will be mentioned here only, and are sul- 
phate, chloride, metals, iron especially, from the subliming 
apparatus, and empyreumatic substances. The latter are 
present if a solution of a salt discharges the color of 
potassium permanganate in presence of sulphuric acid. 

The crude ammonium chloride, or sal-ammoniac, as it is 
called, usually occurs in tough, fibrous masses, or, when 
purified, in granular form. The former is used largely in 
batteries, and the latter for medicinal purposes. 

Ammonia-Water. Aqua Ammonice. NH^OH. — This prepa- 
ration is a solution of ammonia, NHg, in water to the extent 
of 10 per cent, by weight. It is made by heating pieces of 
lime, water and ammonium chloride in a retort and con- 
ducting the ammonia gas into water: H^O + CaO = 
Ca(OH),. Ca(OH), + 2NH,C1 = Oa01,+ 2H,0 + 2NH3. 
NH3-]- H,0 = NH^OH. It is more conveniently made by 
diluting the 

Stronger Water of Ammonia, Aqua AmmonicB Fortior, which 
is made as the above, the gas being passed into water until 
the latter is saturated, or until it contains 28 per cent, by 



202 PHAEMACEUTICAL AKD MEDICAL CHEMISTEY. 

weight of the gas. The two preparations differ only in 
strength. They both have an excessively pungent odor, 
acrid and alkaline taste, and strongly alkaline reaction. 
They differ chemically from the potass, and sod. solutions 
in being volatile and in emulsifying fats instead of 
saponifying them. The specific gravity of the stronger 
water is 0.90; that of the weaker, 0.96. Both should be 
kept in well-stoppered bottles in cool places. 

Ammonia Liniment. Linimentum Ammonics, Volatile Liniment — 
Ootton-seed oil is emulsified with water of ammonia and a 
little alcohol added. The liniment should always be well 
shaken before being applied, and should be made when 
wanted. The alcohol aids in binding together the oil and 
the solution. 

Spirit of Ammonia. Spiritus Ammonias. — Spirit of ammonia 
is a solution of 10 per cent, of NHg in alcohol, and is obtained 
by heating the stronger water of ammonia and conducting 
the gas thus volatilized into alcohol. Ammonia-water is 
often, but erroneously, called "spirit of ammonia.^' 

Aromatic Spirit of Ammonia. Spiritus Ammonice Aromaticus. 
— This is a solution of ammonium carbonate and ammonia- 
water in alcohol and water, and flavored with the oils of 
nutmeg, lemon and lavender-flowers. It is intended for 
internal use, and is a very valuable stimulant and antacid. 
When first made it is colorless, but it gradually becomes 
darker, owing to the action of the ammonia upon the oils 
and upon the alcohol. Precipitation often takes place, 
which is due to the ammonium carbonate employed. The 
official salt contains some bicarbonate, which the added am- 
monia-water changes to the carbonate; but if the official salt 
has been exposed, or if it has effloresced, it contains more 
bicarbonate than the ammonia-water can convert into car- 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 203 

bonate, and it is this excess of ammonium bicarbonate 
which forms the precipitate which sometimes deposits in 
the preparation, it being insoluble in the mixture of alco- 
hol and water. 

Ammonium Carbonate. Ammonii Carbonas. NH^HOOg.NH^- 
NHjCOg. — This salt is not a true carbonate, but consists 
of a mixture of one molecule of Mcarhonate and one of car- 
hamate. It is made from calcium carbonate and ammonium 
chloride; in this process double decomposition takes place 
according to the following reaction: 2Ca003 +4jN'H^C1 = 
2CaCl, + H,0 + NH3 + (]S[H,H003]SrH,NH,C0 J. If one 
molecule of water is added to the carbamate a neutral car- 
bonate is produced, thus: NH,NH,C0,+H,0=(NHJ,C03 
This happens when the pharmacopoeial salt is dissolved in 
water, the resulting solution containing the acid and 
neutral carbonates. By exposure to air or long keeping 
the salt loses ammonia and carbonic acid gas, the propor- 
tion of bicarbonate thereby increasing. Ammonia-water 
converts the bicarbonate into the carbonate. 

Ammonium carbonate is usually in form of translucent 
masses, of very pungent and ammoniacal odor, alkaline, 
and partly soluble in alcohol, the bicarbonate remaining 
undissolved. The chief and objectionable impurity in this 
salt is empyreumatic matter, which communicates to the 
salt a smoky odor, and whose presence is an indication of 
incomplete purification. 

Solution of Ammonium Acetate. Liquor Ammonii Acetas. 
l^Hfi^Hfl^. — Ammonium carbonate is employed in making 
this solution, which is often called Spirit of Mindererus. 
It is neutralized by dilute acetic acid : NH^H003.]SriI^NH,- 
00, + H,0 -f 3HO,H30, = 3NH,C,H30, + 200, + 2H,0. 



204 PHARMACEUTICAL A:N"D MEDICAL CHEMISTRY. 

This preparation should be freshly prepared when needed, 
and should be very slightly acid. 

Ammonium Benzoate. Ammonii Benzoas. NH^C^H^O^. — Con- 
veniently made by dissolving benzoic acid in ammonia- 
water, or by adding benzoic acid to solution of ammonium 
carbonate. ISFH^OH + HC,H,0, = NH^O^H^O, + H,0. 
The benzoate should be crystallized from a slightly alkaline 
solution to prevent the formation of the acid benzoate. 
The salt emits ammonia and benzoic acid vapors when 
strongly heated, and with solution of sulphate of iron con- 
taining a little nitric acid it produces a flesh-colored pre- 
cipitate. By treatment with an acid the benzoic acid 
separates. 

Ammonium Bromide. Ammonii Bromidum. ISTH^Br. — This salt 
may be made by dissolving bromine in ammonia-water or 
by a double decomposition between ammonium sulphate and 
potassium bromide: (NHJ,SO,+2KBr = 2NH,Br+K,SO,. 
The addition of alcohol to the solution causes the potassium 
sulphate to precipitate. This salt is sometimes made from 
ferrous bromide and ammonium carbonate. See p. 185. 
Ammonium bromide loses some of its iodine upon exposure 
and becomes yellow. The Pharmacopoeia allows the pres- 
ence of one per cent, chloride. 

Ammonium Nitrate. Ammonii Nitras. NH^NOg. — If am- 
monium carbonate is treated with diluted nitric acid until 
effervescence ceases and the solution evaporated, crystals of 
nitrate of ammonium will be formed. Sometimes the evap- 
oration is carried to dryness, to obtain the salt in masses 
or in granular form : 

NH.HCOg.NH.NH.CO, + H,0 + 3HNO3 = 

3NH,N03+ 2C0, + 2H,0. 
The chief use of this salt is to prepare the nitrous oxide 



PHARMACEUTICAL AND MEDICAL CHEMISTEY. 205 

used as an anesthetic in dentistry. The laughing-gas is 
obtained by simply heating the nitrate : NH^NOg + heat 
= N,0 + 2H,0. 

Ammonium Valerianate. Ammonii Valerianas. NH^O^HgO^. 
— Double decomposition between valeric or valerianic acid 
and ammonia-water or ammonium carbonate produces am- 
monium valerianate. Among the several methods employed 
in making this salt the best is to pass ammonia gas into 
solution of valeric acid: HO,H,0, + ^^, = NH,, 0,H,0,. 
It occurs in white flakes, is deliquescent, has strong odor of 
valeric acid and is usually of acid reaction, though it should 
be neutral. It is a nervine and is largely used to prepare 
the popular elixir of ammonium valerianate. The com- 
mercial salt usually contains an excess of acid. It is very 
soluble in alcohol. 

Ammonium Iodide. Ammonii hdidum. NHJ. — Obtained by 
double decomposition between pqtassium iodide and am- 
monium sulphate: (NHJ,SO,+ 2X1= 2NHJ + K^SO,. 
The potassium sulphate is made to crystallize first from 
the solution by the addition of alcohol and reduction of 
temperature. The salt is not permanent in the air, soon 
becoming yellow from the liberation of iodine. It should 
be white and odorless. It is soluble in alcohol, and is used 
in much the same indications as potassium iodide. 

Lithium Salts. 

Lithium is the last of the alkalies left for study. The 
metal is peculiar in that it is the lightest of all known 
metals, being a little more than half as heavy as water; 
specific gravity, 0.589. Its salts resemble very closely those 
of potassium and sodium; they are all white or colorless, 
soluble in water, excepting the carbonate, which is only 



206 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

slightly soluble. The benzoate and carbonate are permanent 
in air; the others are very deliquescent. Lithium is widely 
distributed in nature, but always occurs in very small 
quantities. The impurities likely to be found are prin- 
cipally salts of other alkalies and of alkaline earths. The 
sources of the lithium salts are at present the minerals 
spodumene and lepidolite, from which^ by a circumstantial 
process, the carbonate is prepared, this in turn yielding all 
the other salts. 

Lithium and its salts are easily detected by the flame, to 
which they give a vivid red color. Sodium phosphate or 
ammonium carbonate gives a white precipitate in concen- 
trated solutions of lithium salts of neutral or alkaline 
reaction. The precipitate is dissolved by acids or by am- 
monia-water. Lithium is a monad; atomic weight, 7.01. 

Lithium Carbonate. LithU Carbonas. Li^COa. — This is the 
salt obtained from the natural combinations of lithium, by 
first converting the latter into the sulphate, and precipitat- 
ing the lithium carbonate by ammonia carbonate. It dis- 
solves in acids with effervescence, producing corresponding 
salts; is soluble in 80 parts of water and insoluble in alcohol. 
It is frequently administered in cases of gouty affections. 

Lithium Benzoate. LHhii Benzoas. ^iQ^HJd^^. — Is prepared 
by heating together lithium carbonate and benzoic acid 
until effervescence ceases, filtering, evaporating and crys- 
tallizing. Sometimes the evaporation is carried on to dry- 
ness : Li,003 + 2H0,H,0, = 2LiC,H,0, + CO, + H,0. 
The benzoate is soluble in water and alcohol, is of slightly 
acid reaction, and has an odor of benzoic acid. Its prin- 
cipal use is in the treatment of gout, although it is also 
used extensively as a means of dissolving urinary calculi. 

Lithium Bromide, LithU Bromidum. LiBr. — The bromide 



PHAEMACEUTICAL AifD MEDICAL CHEMISTRY. 207 

results when ferrous bromide is decomposed with lithium 
carbonate, lithium bromide remaining in solution while 
the ferrous carbonate precipitates — e.g., FeBr, + Li^COg 
= FeCOg + 2LiBr. This salt is the most deliquescent of 
the lithium salts, is very soluble in alcohol, and is a reli- 
able hypnotic administered in doses of 0.50 to 2.00 gms. 

Lithium Citrate. Lithii Citras. LigOgH^O,. — If to a warm 
solution of citric acid lithium carbonate is added as long 
jis effervescence lasts, a solution of lithium citrate will be 
formed from which the salt is obtained by evaporating to 
dryness: 2H30,H,0, + SLi.COg = 2Li30,H,0, -h 3C0, 
+ SH^O. The citrate is used as the carbonate is and for 
same medicinal purpose. 

Lithium Salicylate. LHhii Salicylas. LiO^H^O^. — If i'nstead 
of using citric acid, salicylic acid is employed, lithium 
salicylate results: Li^COg + 2HC,H,03 == 2LiO,H,03 + H,0 
+ CO3. This salt is often used in place of sodium sali- 
cylate for rheumatism. 

The Metals of the Alkaline Earths. 

The three metals constituting this group, calcium, ba- 
rium and strontium, have some similarity to the alkalies, 
especially in their action upon vegetable colors when in 
form of oxide or hydroxide, whence their name, alhaline 
earths. They have also a similar taste and caustic action. 
The three metals are each dyad; they form only one 
chloride each, and their carbonates and sulphates are 
practically insoluble. 

Calcium Salts. 

This metal occurs very abundantly and widely diffused 
in nature, but never in the free state. The metal is not 



208 PHARMACEUTICAL Al^D MEDICAL CHEMISTRY. 

unlike gold in some respects physically — it has a light- 
yellow color, is very ductile, easily cut or filed, and capable 
of being hammered into very thin sheets. It differs from 
gold in being much lighter in weight, in tarnishing in the 
air, and in being quickly acted upon by water and dilute 
acids. 

Sources. — The chief sources of calcium and its salts are 
the carbonate, which occurs in a great variety of forms: 
limestone, marble, chalk, Iceland spar, calcite, stalagmites, 
shells of oysters and of other cretaceous animals; the phos- 
phate in the mineral apatite and in bones of vertebrates ; 
and the sulphate as gypsum (native calcium sulphate). 
There are many otiier forms of occurrence, but the above 
are the more important ones. 

Prepared Chalk. Creta Prceparata. CaOOg.— The greater 
number of the pharmacopoeial salts of calcium are made 
from the carbonate, which occurs in the numerous forms 
mentioned above. The native friable carbonate, known as 
chalk, is purified simply by a process of elutriation, which 
consists of trituratiug the chalk to a very fine powder in a 
slow stream of water, which flows into a series of tanks, each 
of which is somewhat lower than the one next to it, so that 
each becomes filled by the overflow of the next higher one. 
The coarser and heavier particles are deposited in the first 
tank, the lighter ones passing with the overflow into the next, 
where more of the heavier particles settle; the last tank 
usually has deposited in it very fine particles of chalk, 
which constitute the prepared chalk of the U. S. P. While 
still in the moist condition it is sometimes shaped into 
small cones, when it forms the "drop chalk" of the stores. 
This preparation is used in preference to any other kind 
of carbonate in medicine. It is antacid, and enters into 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 209 

the Compound Chalh Powder, which contains in addition 
some acacia and powdered sugar, and which, when sus- 
pended in cinnamon-water, constitutes the popular Chalk 
Mixture of the U. S. P. 

Prepared chalk may contain traces of barium, strontium, 
iron and magnesium as impurities. It is readily soluble in 
hydrochloric acid. 

Precipitated Calcium Carbonate. CalcH Carbonas Proecipi- 
fatus. OaCOg. — The prepared chalk is not very pure chem- 
ically, so that the U. S. P. adopted another form of the 
carbonate, made by precipitating calcium chloride with 
sodium carbonate. The chloride is made from the car- 
bonate obtained in nature by treatment with hydrochloric 
acid; the process therefore begins with a carbonate and 
ends with a carbonate : 

Ca003 + 2HC1 = CaOl, + H,0 + CO, 
CaOl, + Na,C03 = 2Na01 + GaOOg. 

This process yields a very finely-divided powder, usually 
very pure. It is less valuable than the prepared chalk for 
internal administration, but is used very largely in tooth- 
powders. 

Troches of Chalk. — Chalk troches contain each 4 grains 
of prepared chalk, besides powdered gum arable, sugar and 
nutmeg, made into a mass with water. 

Calcium Chloride. Ca/cii ChloHdum. CaCl,. — Made, as 
shown above, from chalk and hydrochloric acid. It is very 
deliquescent, and is chiefly used in chemical operations for 
removing watery vapors from gases. It is also largely used 
for keeping the air dry in glass-cased balances or electric- 
machines. It should be kept in bottles securely corked. 

Calcium Bromide. Calcii Bromidum. CaBr,. — Of several 



210 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

methods for preparing this salt, the simplest consists 
in adding precipitated chalk in excess to hydrobromic 
acid, filtering, evaporating to dryness or granulating: 
CaC03 + 2HBr = OaBr, + H,0 -f- 00,. This is a very de- 
liquescent salt, and needs to be kept in well-stoppered bot- 
tles. Its value depends on the bromine which it contains; 
it is a hypnotic and is given in doses of 0.50 to 2.00 gms. 

Lime. Calx. OaO. — This is oxide of calcium, CaO, and 
is made by expelling the CO^ from the carbonate by means 
of heat : CaCOg -j- heat = CaO + OO,. Its chief use is 
in building; in pharmacy it furnishes lime-water, chlorin- 
ated lime, sulphurated lime and syrup of lime. It is often 
used for dehydrating purposes, as the chloride is; when it 
comes in contact with moisture or water it unites with it, 
producing the hydroxide : CaO + H^O = Ca(0H)2. Ex- 
ternally it is a caustic and an escharotic, and enters into 
preparations for removing hair from the skin. 

Lime-Water. Liquor Ca/cis, Ca(0H)2. — Lime is slightly 
soluble in water, and when dissolved in it to saturation 
furnishes lime-water, which contains about 0.17 per cent 
of calcium hydroxide, Ca(0H)2. It is peculiar with many 
calcium salts that they are more soluble in cold water than 
in hot, and in making lime-water cold water should invari- 
ably be employed, since it is desired to get the largest 
amount of lime in solution. It is given to children to check 
nausea. 

Syrup of Lime. Syrupus Ca/cis. — Lime is more soluble in 
a solution of sugar than in water alone, and syrup of lime 
is a solution of lime made by boiling lime and sugar in 
water. It contains about 6.5 per cent of lime, which is a 
greater percentage than is in the Liq. Calcis, and hence it 
is more alkaline. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 211 

Lime Liniment. Linimentum Calcis. — Equal parts of lime- 
water and cottonseed oil well shaken together constitute 
the lime liniment which is so largely used as application 
to burns, scalds, etc. The physicians prescribe it at times 
under the name " carron oil." 

Sulphurated Lime. Calx Sulphurata. Crude Calcium Sul- 
phide, CaS, and OaSOJ. — About equal parts of lime and 
precipitated sulphur are fused together in a crucible for an 
hour or longer, and the resulting product preserved in 
small, well-stoppered bottles. A chemical combination takes 
place producing varying quantities of calcium monosul- 
phide and sulphate, but at least 60 per cent of the former 
should be present. This preparation when made into paste 
with water is an excellent depilatory. In small proportions 
it is sometimes used in ointments for skin-diseases, and at 
times internally for a similar purpose. 

The U. S. P. of 1890 directs this preparation to be made 
by reducing the calcium sulphate to sulphide with charcoal 
and starch. Some of the sulphate remains unchanged. 

Chlorinated Lime. Calx Chlorata. 30a(OH)2.— Chemically 
this is a mixture of calcium chloride and hypochlorite: 
20aO -f 201, + H,0 = (OaOl, f Ca(ClO),) + H,0. It is 
a grayish- white powder, should not be more than slightly 
damp, has an odor of chlorine, and should be kept in 
securely-closed vessels. It is employed very extensively in 
the ^rts for bleaching and in the household for disinfect- 
ing. Its value always depends upon the amount of avail- 
able chlorine which it contains, and which should never be 
less than 35 per cent. See page 78. 

Labarraque's Solution has received mention under chlor- 
ine; it is prepared by acting on chlorinated lime with 
soda carbonate. See page 80. 



212 PHARMACEUTICAL Ai^TD MEDICAL CHEMISTRY. 

Calcium Hypophosphite. Calcii Hypophosphis. Q^^^R^VO^^. 
— The making of this salt involves some danger, owing to 
the employment of phosphorus and because oi the genera- 
tion of the spontaneously-inflammable phosphoretted hy- 
drogen. Calcium hydroxide (slaked lime) suspended in 
water is boiled with phosphorus and the gases formed 
conducted by means of a hood or draught into the 
chimney, or into the air, as quickly as they are generated: 
3Ca(0H), + 8P + 6H,0 = 2PH3, phosphoretted hydro- 
gen, -f 30a(H2P02)2, calcium hypophosphite. A little of 
the insoluble phosphate, Qq>^{VO^^, is formed, which is re- 
moved by filtration. The solution is evaporated and the salt 
granulated or allowed to crystallize. In evaporating ex- 
treme care should be taken not to permit the temperature 
to rise above 180° F. for fear of explosion. The salt should 
never be kept in warm places, as it is very liable to explode 
and disengage the powerfully-poisonous PH3. This is a 
salt which the pharmacist is wise to buy from a reliable 
house. It enters into the Syrup of HypopJiospMtes, and is 
usually employed to make the other hypophosphites of the 
IT. S. P. and of the market. 

Precipitated Calcium Phosphate. Calcii Phosphas PrcBcipitatus. 
Ca3(P0j2- — Calcined bones are dissolved in hydrochloric 
acid and the solution precipitated with ammonia-water, 
the precipitate thoroughly washed or strained and dried. 
Bones contain the phosphate of calcium, and in order to 
obtain this in a finely-divided state it is caused to enter 
solution, from which it is precipitated as a fine powder. It 
is a permanent powder, insoluble, and used for distributing 
the oils in making the aromatic waters. It is better adapted 
for this purpose than magnesium carbonate, because of its 
greater insolubility. Its principal use was in preparing the 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 213 

8yrup of Lactophosphate of Calcium, U. S. P. 1880, which 
was made by dissolving the freshly-prepared phosphate in 
lactic acid and mailing into syrup with sugar and flavoring 
with orange-flower water. The 1890 U. S. P. directs the 
precipitated carbonate in place of the phosphate in making 
the syrup of lactophosphate of calcium. 

Strontium Salts. 

The strontium salts have lately been introduced into 
therapeutics, and they seem designed to occupy a very 
prominent place in the modern materia medica. Their use 
in medicine was so long deferred because of the belief that 
they were poisonous. The Prench physiologist. Dr. La- 
borde, however, lately proved that the toxic properties of 
salts of strontium were due to the presence of the poison- 
ous barium, and that when the latter is removed the pure 
strontium salts are therapeutic agents of such value as to 
likely replace, it is predicted by some, the alkali and 
alkaline-earth salts in medicine. The first to prepare 
chemically pure strontium salts was the French chemist 
Paraf-Javal. All the natural compounds of strontium: 
strontianite, a carbonate; celestine, a sulphate, and others, 
contain barium, which is removed with difficulty in the 
process of purification. Every pharmacist should there- 
fore examine his strontium salts for barium. This is 
easily accomplished by adding a few drops of dichromate 
of potassium test-solution (a ten per cent solution) to a 
solution of one part salt in 20 of distilled water — a tur- 
bidity would indicate the presence of barium and the need 
to reject the salt. 

Properties and Tests for Identity and Purity.— The 



214 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Pharmacopoeia recognizes three strontium salts, the bro- 
mide, the iodide and the lactate. They are all hydrous, 
the lactate containing three molecules of water and the 
bromide and iodide six each. The application of heat at 
first melts the salts, then fuses them causing the loss of their 
water of crystallization; a higher heat decomposes them. 
They impart an intense red color to a non-luminous flame. 
They are easily soluble in water; the lactate is permanent 
in the air, while the bromide and iodide are very deli- 
quescent and prone to decomposition, for which reason 
they should be kept in well-stoppered bottles. 

Each of the salts in solution is precipitated as sulphate 
with the solution of any soluble sulphate. Calcium sul- 
phate is very sparingly soluble in water, but yet its solu- 
tion will precipitate strontium, showing that the strontium 
sulphate is less soluble than the calcium sulphate. 

Potassium chromate solution forms a yellow precipitate 
of strontium chromate in solutions of strontium salts. 
Soluble carbonates also precipitate soluble strontium salts. 

A l-in-20 aqueous solution should not be affected by hy- 
drogen sulphide, either before or after acidulation with a 
drop of hydrochloric acid — this would indicate the absence 
of arsenic, lead, copper. Ammonium sulphide test-solu- 
tion (H^S passed into ammonia-water to saturation) should 
not alter the aqueous solution, which would indicate the 
absence of iron, aluminum and other metals. 

Strontium Bromide. strontH Bromidum. SrBr^ + GH^O. — 
This salt may be obtained by treating hydrobromic acid 
with strontium carbonate, filtering, evaporating and crys- 
tallizing : SrC03 + 2HBr = SrBr, + H,0 + CO,. The 
carbonate should be pure. The bromide also results if 
strontium is burned in bromine vapor. The salt is odor- 



\ 



PHAEMACEUTICAL Ai^D MEDICAL CHEMISTRY. 215 

less, has a bitter alkaline taste, and occurs in forms of 
colorless, transparent, six-sided crystals. Properties are 
given above. 

Medicinally the bromide is recommended as a substitute 
for the bromides of other bases in the treatment of epilepsy 
and allied conditions. 

Strontium Iodide. Strontii lodidum. Srl^ + 6H„0. — If a 
solution of hydriodic acid is saturated with strontium hy- 
droxide, the strontium iodide results, which may then be 
obtained by evaporation: 2HI + Sr(OH), = Sri, + 2H,0. 
The iodide is in transparant, colorless plates, odorless, 
bitterish taste, deliquescent. It turns yellow if exposed to 
air and light, due to the liberation of iodine, and hence 
should be kept well preserved in small dark, amber-colored 
glass-stoppered bottles. See properties above. 

Medicinally the iodide is claimed to have the alterative 
action of iodides, but without depressing the general nutri- 
tion, or irritating the intestinal canal. 

Strontium Lactate. Strontii Lactas. Sr(03H,03)2 + SH^O. 
— Strictly pure strontium carbonate is dissolved by means 
of gentle heat in absolute lactic acid diluted with water : 
SrOO, + 2HC,H.O, = SrCC.H.O,), + H.O + CO,. The 
salt is obtained from the solution by evaporating and granu- 
lating. The salt occurs in form of a white granular powder 
or crystalline nodules, odorless, permanent in the air. For 
other properties and tests see above. 

The lactate is claimed to be a successful remedy in the 
treatment of nephritis and chronic albuminuria. Dose, 
0.65 to 1.95 Gm. 



216 PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 

Barium. 

The salts of this metal are not of sufficient interest to 
the pharmacist to merit more than mention. The chloride 
of barium is a very useful reagent in solution for sulphates, 
the sulphate of barium being wholly insoluble: BaCl^ 
-f Na^SO, = BaSO, + 2NaCl. 

The dioxide, BaO^, is employed in the preparation of per- 
oxide of hydrogen, and the nitrate and hydroxide dissolved 
in water are used as test solutions. 

Magnesium Salts. 

Magnesium occurs in a great variety of combinations and 
is widely distributed throughout nature, but pharmacy 
derives its supply at present chiefly from the silicious hy- 
drate found in the serpentine rocks of New Jersey, Penn- 
sylvania and Ohio. The principal source formerly was the 
sulphate obtained from the Epsom Springs, in England. 

The word ^'^ magnesia ^Ms derived from the nauie of a 
town in Asia Minor in the neighborhood of which two 
minerals were found in abundance, one of a white color 
named magnesia alba, and the other of a blackish color 
termed magnesia nigra. The former was that which we 
now know as magnesium carbonate, while the latter is the 
manganese dioxide, called manganese to distinguish it from 
magnesium. 

Tests for Magnesium Salts. — Sodium phosphate solution 
produces, in presence of ammonia-water, a white crystalline 
precipitate of NH^MgPO^, ammonio-magnesium phosphate. 

The caustic alkalies produce white gelatinous magma- 
like precipitates. The presence of ammonium chloride 
prevents the formation of these precipitates. 



PHARMACEUTICAL ANB MEDICAL CHEMISTKY. 217 

Any soluble carbonate gives with soluble magnesium 
salts a copious white precipitate. 

Magnesium Sulphate. MagnesH Sulphas. M-g^O^.l^fi. — 
The sulphate is made from the mineral serpentine by di- 
gesting the latter with sulphuric acid, dissolving out the 
sulphate produced and crystallizing. Some years ago it 
was almost exclusively obtained by evaporating the water 
from Epsom Spring, in England, which contained a large 
proportion of the salt in solution. All other salts are 
made from the sulphate. It is in small colorless prisms, 
or acicular needles, efflorescent in dry air, very soluble in 
water, insoluble in alcohol. The impurities likely to be 
present, and consequently likely to be present in all of the 
salts made from it, are chlorides, metals, alkaline earths 
and alkalies; the U. S. P. permits the presence of 1 per 
cent of the sulphates of the alkalies. Epsom salt is purga- 
tive in 1 or 2-ounce doses. Oxalic acid is sometimes mis- 
taken for it, although there is a great dissimilarity between 
the crystals. 

Magnesium Carbonate. MagnesH Carbonas. (Approximately 
Mg003)4.Mg(OH)2.5H20. — The composition of magnesium 
carbonate varies somewhat. It always contains hydroxides, 
and the salt recognized by the IT. S. P. probably contains 
one molecule of the hydroxide and four of the carbonate, as 
the formula indicates. There are two carbonates, a light 
and a heavy one, both made by the same process, the differ- 
ence being merely in the employment of dilute or concen- 
trated solutions of sodium carbonate and magnesium sul- 
phate: 5MgS0, + 5Na,C03 + H,0 = (MgC03),.Mg(0H), 
+ SNa^SO^ -\- CO^. The carbonate precipitates and, when 
thoroughly washed on a muslin or calico strainer, is dried. 
Concentrated solutions produce the heavy carbonate. 



218 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

which is that recognized by the Pharmacopoeia, and which 
occurs as a light white powder or in friable blocks or 
masses, insoluble, odorless, tasteless. It is employed in 
making the heavy magnesia, solution of magnesium citrate, 
mixture of magnesia and asafa3tida of the 1880 U. S. P., 
etc. It is sometimes employed to diffuse the oils in making 
the medicated waters. Medicinally it is an antacid. 

Magnesia. Magnesia. MgO. — This is the light magnesia 
or calcined magnesia, made from liglit carbonate by ex- 
pelling the CO,: MgC03 + heat = MgO + 00,. I* is a 
very light, white, insoluble powder, very bulky, odorless, 
earthy taste, and alkaline when moistened with water. 
Magnesia is laxative, and is usually combined with powdered 
rhubarb. 

Heavy Magnesia. Magnesia Ponderosa. MgO. — This corres- 
ponds in composition and all properties to the above, 
differing from it only in being heavier. It is made by ex- 
pelling the CO, from the heavy carbonate. 

Solution of Magnesium Citrate. Liquor Magnesii Citratis. — 
This very popular refrigerant laxative is a freshly prepared 
solution of magnesium citrate flavored with lemon and 
sugar, and made refrigerant and sparkling by confining the 
CO, disengaged from potassium bicarbonate: SMgCOg -f- 
2H.C.H.0, = Mg,(C.H.O,)., + 3H,0 + 3C0,. Sometimes 
the calcined magnesia is employed in place of the carbonate; 
the disengagement of the CO, is thereby obviated. The 
solution is kept in strong 12-ounce bottles, with the cork 
tied tightly over the neck of the bottle to prevent its being 
forced out by the CO, from the potassium bicarbonate. 
The latter coming in contact with the citric acid, which is 
always in excess, loses its CO, by double composition accord- 



PHARMACEUTICAL Ai^D MEDICAL CHEMISTRY. 219 

ing to this reaction: 3KHCO3 + H30,H,0, = K30,H,0, 
(potassium citrate) -|- SH^O -J- SOO^. 

Effervescent Magnesium Citrate. Magnesii Citras Efferves- 
cens. — This effervescent salt is made by mixing intimately 
magnesium carbonate, sodium bicarbonate, powdered citric 
acid and sugar, and rubbing to a paste with alcohol. This 
paste is then passed through a coarse sieve and dried. 
When brought into contact with water, solution of the acid 
and bicarbonate takes place, and they react upon each other 
and upon the carbonate and produce effervescence through 
the liberation of CO,. It is essential to keep this prepara- 
tion in well-closed bottles. 

Magnesium Sulphite. MgS036H20. — Prepared by passing 
pure sulphurous acid gas into magnesia suspended in 
water : MgO + SO^ = MgSOg. The sulphite is less soluble 
than the sulphate. It is employed very much as the 
sodium and potassium sulphites are. It is a white crys- 
talline powder which oxidizes by exposure to air. It is no 
longer official. 

Zinc Salts. 

The metal zinc is official in form of irregular granulated 
pieces or in thin sheets, or moulded into thin pencils, or in 
a state of fine powder. It is obtained from calamine, the 
chief source of the zinc salts, by roasting with charcoal and 
collecting the zinc vapors in water. It is a dyad metal 
with an atomic weight of 65, combining with numerous 
acids to form salts. The principal use to which the metal 
is put is to form the sulphate, from which most of the other 
salts are made. It is also employed in considerable quantity 
for the preparation of hydrogen from sulphuric acid: 
HjSO^ -\- Zn = ZnSO^ -\- H^. The metal is often contami- 



220 PHAEMACEUTICAL AND MEDICAL CHEMISTEY. 

nated with arsenic and in delicate analytical work it is 
necessary to ^orovide for its freedom from this contamina- 
tion. The official zinc salts are colorless. 

Analytical Ee actions. — The alkaline hydroxides give 
white precipitates in neutral solutions of zinc salts, which 
precipitates are soluble in excess of the hydroxides. 

Soluble carbonates produce white precipitates of zinc 
carbonate in solutions of zinc salts. 

Sulphuretted hydrogen in alkaline solution or ammonium 
sulphide yields white precipitate of zinc sulphide. 

Zinc Sulphate. Zinci Sulphas. ZnSO^.TH^O. — White vitriol, 
as this salt is often termed, is the product of the reaction 
of dilute sulphuric acid upon zinc, as shown above. The 
solution is evaporated and allowed to crystallize, and is puri- 
fied by recrystallization. The salt is in colorless prisms or 
acicular needles, efflorescent in dry air, odorless, nauseous 
taste, and very soluble in water. 

The impurities likely to be present in this and the salts 
made from it are chloride, iron, copper, lead, alkaline 
earths and alkalies. 

Medicinally it is used externally as an astringent anti- 
septic, and internally as a very prompt emetic, in doses of 
from 0.50 to 2.00 Gms. In large doses it is poisonous, and 
care should be exercised not to mistake it for other harm- 
less salts, such as epsom salts, etc. 

Zinc Bromide. Zinci Bromidum. ZnBr^. — Potassium brom- 
ide in solution with zinc sulphate produces double decom- 
position, yielding zinc bromide and potassium sulphate, 
which both remain in solution, and from which the sulphate 
is precipitated by the addition of alcohol. The remaining 
solution of the bromide is evaporated to dryness or the salt 



PHARMACEUTICAL Al^D MEDICAL CHEMISTRY. 221 

is granulated. Among a number of methods that just 
described is regarded as the best. 

The salt thus obtained is very deliquescent, odorless, 
of sharp taste, very soluble, and may contain all of the im- 
purities mentioned under sulphate. The medicinal value 
of the salt is due to the bromine present. It is occasionally 
prescribed for the relief of insomnia. 

Zinc Valerianate. Zinci Valerianas. 7iYi{G^B.fi^)^2llfi. — 
The zinc sulphate is precipitated by sodium valerianate, and 
zinc valerianate rises to the surface in the solution, contrary 
to the usual phenomenon that precipitates deposit: 2Na- 
C,H,0,+ ZnSO,= Zn(0,H,0,),+ N"a,SO,. The salt occurs 
in white pearly scales, is permanent, slightly soluble in 
water, and has a faint odor of valerianic acid. It is a form 
for the administration of valerianic acid and possesses the 
same medicinal properties, being used as an antispasmodic 
and nerve tonic in doses of 0.03 to 0.18 Gm. 

Precipitated Zinc Carbonate. Zinci Carbonas Prcecipitatus. 
(ZnC03)23Zn(OII)2. — Zinc sulphate is precipitated by 
sodium carbonate and the resulting insoluble carbonate 
thoroughly washed with hot water : SZnSO^ -|- SNa^OOg + 
3H3O = (Zn003),3Zn(OH), + 5Na,S0, + 300,. The for- 
mula will show that the " carbonate," so called, is really a 
mixture of carbonate and hydroxide. It is an impalpable 
powder, insoluble except in acids, odorless and tasteless. 
This carbonate is much finer and purer than the native 
carbonate, calamine, could conveniently be made. Its prin- 
cipal use is for external application, either as powder or in 
form of ointment. 

Zinc Oxide. Zinci Oxidum. ZnO. — The carbonate, made as 
above, when calcined, loses its 00,, becoming ZnO — e.g., 
ZnCOg + heat = 00^ + ZnO. Much of the commercial 



222 PHAEMACEUTICAL AI^D MEDICAL CHEMISTEY. 

oxide is made from calamine^ but for medicinal purposes 
only the very finest, made from the precipitated carbonate, 
should be employed. The oxide is a soft, whitish powder, 
permanent in the air, insoluble and without odor or taste. 

Zinc Oxide Ointment. — An ointment made by incorpo- 
rating 20 per cent of the finest quality of zinc oxide with 
benzoinated lard. 

Zinc Acetate. Zinci Acetas. Zn{CJtLfi^)^.2B.fi.—Bsisily 
prepared by adding excess of zinc carbonate to acetic 
acid, filtering and evaporating the solution or setting it 
aside to crystallize. (ZnC03),3Zn(OH), + 10HO,H3O, = 
5Zn(C,H30J, + 2C0, + 8H,0. Zinc acetate is in soft, 
pearly scales or tablets, efflorescent in dry air; it is soluble 
in alcohol and water, has a faint odor of acetic acid, and 
sharp, metallic taste. 

Zinc Iodide. Zinci lodidum. Znl. — Zinc and iodine are al- 
lowed to remain in contact in water until solution takes 
place: Zn -[- I^ = Znl^. The solution is evaporated and the 
salt obtained in granular form usually. It is a white, gran- 
ular powder, very deliquescent, without odor. Its use in 
similar to that of potassium iodide. 

Solution of Zinc Chloride. Liquor Zinci Chloridi. ZnOl,. — 
Zinc is dissolved in hydrochloric acid; the solution, to 
which some nitric acid has been added to oxidize any iron 
present, is then evaporated to dryness and the residue dis- 
solved in water. The second solution is clarified by shaking 
with zinc carbonate, which precipitates any iron that may 
be still present, as a carbonate: Zn -f 2HC1 = ZnCl^-f Ha- 
lf iron is present it becomes FeCl,, thus: Fe + 2H01 == 
FeOl^ -{- Hj. The FeCl^, ferrous chloride, is oxidized to 
the ferric chloride with the nitric acid and more HCl, thus: 

6Fe01, + 6HC1 + 2HNO3 = 3Fe,Cl, + 4H,0 + N,0,. 



I 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 223 

The Fe^Cl, when heated probably decomposes into the 
insoluble ferric oxide and HCl, the latter volatilizing : 
Fe^Ol, + heat + 3H,0 = Fe,03 + 6HC1. Any Fe^Cl, re- 
maining unoxidized is removed by the addition of the zinc 
carbonate, which produces the insoluble ferric hydroxide 
and carbonate : Fe.Ol, + 3Zn003 = Fe,(003)3 + SZnCl,. 
The Fe2(C03)3 together with some hydroxide precipi- 
tates and the ZnOl^ remains in solution with the rest of 
the ZnClj. The Fe2(003)3 usually decomposes with some 
rapidity into Fe,03 thus: Fe,(C03)3 = Fe,03 + SCO,. The 
solution is a clear, colorless liquid, odorless, and is used 
as a disinfecting and antiseptic solution. 

Zinc Chloride. Zinc/' Chloridum. ZnCl^. — A very deliques- 
cent salt, rarely used, made by evaporating the solution of 
zinc chloride. It is used externally as an escharotic, and 
is often mixed with flour and water to mitigate or regulate 
its effect. 

Zinc Phosphide. Zinci Phosphidum. ZUgP^. — Made by con- 
ducting vapors of phosphorus in current of hydrogen over 
heated zinc — a dangerous operation. It occurs in crystal- 
line, brittle fragments, or as grayish powder, insoluble, per- 
manent in air. Zinc phosphide is preferred by many to 
phosphorus for internal administration. Dose, .003 to .006 
Gm. 

Aluminum Salts. 

Aluminiim is one of the most abundant of the metals, 
and occurs very extensively in rocks and clays. Some com- 
pounds are made from cryolite, the fluoride of sodium and 
aluminum, GNaF.Al^Fg, found abundantly in Greenland. 
Many of the precious stones are aluminum compounds, the 
metal itself being of considerable value, owing to the diffi- 



224 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

culty associated with its separation from its compounds. It 
is only a little more than 2^ times heavier than water^ but 
yet has all the valuable qualities of iron, with none of 
its negative properties; it does not tarnish or oxidize in 
the air, and is only about one-fourth as heavy as iron. 
Advantage is taken of its lightness in the manufacture of 
small weights, particularly the grain and smaller divisions 
of the gramme, and delicate apparatus and articles of 
ornament. Among the usual methods for isolating it 
is the reduction of its compounds with metallic sodium or 
potassium. 

It is a trivalent or pseudo-triad (AIJ""^ metal; atomic 
weight, 27; symbol Al. 

Analytical Reactions. — The alkaline hydroxides pro- 
duce gelatinous white precipitates, Al2(0H)g, which are sol- 
uble in excess, excepting in ammonia. The alkali carbon- 
ates yield a similar precipitate, the OO^ escaping: Al2(S0j3 
+ 3Na,C03-f 3H,0 = A1,(0H),+ 3^,80, + 3C0,. Am- 
monium sulphide also precipitates the hydroxides with the 
evolution of hydrogen sulphide: A1,(S0 J3 + 3(NHJ,S + 
6H,0 = A1,(0H), + 3(NHJ,S0, + 3H,S. 

Alum. Alumen. K,A1,(S0 J,24H,0.— This salt is the type 
of all the alums, explained in a previous chapter. It is 
made chiefly from the aluminum silicate in alum-clay by 
appropriate treatment with sulphuric acid, the addition of 
potassium sulphate, and allowing the two sulphates to 
crystallize together with 24 molecules of water. If in 
place of potassium sulphate the ammonium sulphate is em- 
ployed, amm 071111711 alum, (NIL^)^A]^{SOJ^24Rfl, is formed. 

Alum occurs in large octahedral crystals or as white pow- 
der, is odorless, has sweetish, astringent taste, soluble in 
water, and effloresces slightly in dry air. Iron, zinc or lead 



rHARMACEUTICAL AND MEDICAL CHEMISTRY. 225 

may be present as impurities in any of the aluminum com- 
pounds, and may be looked for by the usual tests. 

Alum is one of the best styptics and astringents we 
haye. 

Dried Alum. Alumen Exsiccafum. K,A12(S0J4.— The crys- 
tallized alum when heated loses its water of crystallization 
and becomes the official Alumen Exsiccatum. Exsiccated 
means dried. Alum loses about 45 per cent of its weight 
in the process of drying, and dried alum is more powerful 
than tlie hydrous alum in consequence. 

The loss in weight which a crystallized salt sustains 
upon drying is easily found from the .molecular weights 
before and after drying, f.i. alum before drying is K^Al^- 
(SOJ^24H20, its molecular weight is the sum of the 
weights of the atoms : 

2A1 = 2 X 27 = 54 

2K = 2 X 39 = 78 

4(S0 J, = 4 X (S = 32 + 40 = 64 =)96 = 384 

24H,0 = 24 X (H, = 2 + = 16 =)18 = 432 



Molecular weight of alum = 948 

Upon drying the 24H2O are expelled; hence there is a 
loss of 432; then 948 — 432 = 516, the molecular weight 
of K,A1,(S0.),. 

To express the loss in percentage it is only necessary to 
use the rule of three: 948 : 432 : : 100 : x = 45.57 per cent 
loss. 

100 grains of alum would therefore become dried or 
hurnt alum when the weight would have become reduced 
to 55 grains. 

Aluminum Hydrate. Alumini Hydras. K\^{011)^. — Hydrox- 



226 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

ide would be a better term than hydrate to apply to this 
drying or absorbing and antacid powder. It is made by 
precipitating sodium carbonate by alum and thoroughly 
washing the precipitate with hot water and drying. (See 
reaction above.) The light white powder thus obtained is 
permanent in air, odorless and insoluble. It is used but 
little. 

Aluminum Sulphate. Alumini Sulphas. K\{^OX.l^B.fi. — 
The freshly prepared hydroxide is dissolved in dilute sul- 
phuric acid and the solution allowed to crystallize or 
granulate. It is antiseptic, and seldom or rarely used in- 
ternally. 

Cerium. 

There is only one cerium salt official, the oxalate, and 
that is made by a very circumstantial process, necessitated 
by the association of cerium with the two rare metals lan- 
thanum and didymium. The cerium compounds when 
sufficiently purified are precipitated by oxalic acid. 

Cerium Oxalate. Cerii Oxa/as. 062(0^0^391120. — Is a 
whitish powder, slightly granular, permanent in the air, 
odorless, tasteless, insoluble, soluble in hydrochloric acid. 
Sodium hypochlorite gives a red precipitate in the latter 
solution, soluble in warm HOI, evolving chlorine. Oxalate 
of cerium is regarded as almost a specific for checking 
nausea. Dose, 0.06 to 0.30 Om. 

Lead Salts. 

Of the several combinations in which lead is found in 
nature, the sulphide, or galena, is the one usually chosen 
as the source of the metal and its salts. Galena occurs very 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 227 

abundantly in this country and is usually associated with 
silver, though often found in the free state. The metal is 
extracted from the ore by roasting first in contact with and 
in the latter part of the process without, access of air, or 
by melting with charcoal. 

Lead is a bluish -white, soft, malleable metal, with a per- 
ceptible taste, and an odor when rubbed, little acted upon 
by air, but soluble to a slight extent in very pure water, 
becoming a hydroxide. Water thus impregnated is very 
poisonous, and increases in its toxic qualities if the hydrox- 
ide becomes changed, through the presence of carbon diox- 
ide, into the more soluble bicarbonate. A knowledge of 
this fact should prompt the utmost carefulness in the use 
of lead pipe or leaden vessels of any kind for purposes 
where presence of lead might entail disastrous results. 
There are numerous cases on record where poisoning was 
traced to lead in drinking-water or in mineral-waters drawn 
through leaden pipes. Magnesium sulphate or sodium, 
or highly diluted sulphuric acid, are chemical antidotes. 
Lead is a dyad ; atomic weight, 206.4 ; sp. gr.. 11.45; 
symbol, Pb. 

AiyfALYTiCAL Keactions. — 1. Sulphuretted hydrogen 
produces a black precipitate of the sulphide, PbS. Very 
minute quantities may be detected by this test. 

2. Any soluble iodide gives a characteristic yellow preci- 
pitate of lead iodide, Pbl^. 

3. Soluble sulphates precipitate the insoluble lead sul- 
phate, PbSO,. 

4. Soluble carbonates precipitate the insoluble lead car- 
bonate, PbCOg. 

Lead Oxide. Plumbi Oxidum. PbO.— Litharge is one of the 
five oxides of lead, and is made by roasting the lead ores 



238 PHARMACEUTICAL A:N"D MEDICAL CHEMISTRY. 

in a reverberatory furnace. It is often obtained as a by- 
product in the extraction of silver from argentiferous ga- 
lena. Litharge is a heavy yellowish or reddish powder^ in- 
soluble, colorless, tasteless, remaining unchanged in the 
air. It may contain as impurities traces of alkalies and al- 
kaline earths, zinc and carbonate. From it most of the 
other salts of lead are prepared. 

. Lead Acetate. Plumbi Acetas. Pb(C,H30J,.3H,0.— This 
is the most important of the lead salts used in pharmacy; it 
is easily made by heating together a mixture of lead oxide 
and acetic acid: PbO -h SHC.HgO,^ Pb(0,H30J, + 3H,0. 
If the acetic acid is not pure the salt usually has a smoky 
odor which does not disappear rapidly upon recrys- 
tallization. The commercial salt should not be used in 
pharmacy, but only that made from the purest acetic acid. 
Sugar of lead, as the salt is most frequently called, occurs in 
colorless, shining, prismatic crystals or scales, is soluble in 
alcohol and water, has faintly acetous odor and astringent 
taste, and absorbs carbonic acid from the air. The latter 
is the cause of the turbidity noticed in solutions of the salt. 
This turbidity may be removed by the addition of a little 
acetic acid. Acetate of lead is astringent, and is used ex- 
ternally in solution as a sedative wash, often combined with 
laudanum. 

Solution of Lead Subacetate. Liquor Plumbi Subacetatis. — 
This aqueous liquid, containing about 25 per cent of lead 
subacetate, approximately Fhfi{CJi^O^)^, is obtained by 
boiling together lead oxide and lead acetate in water pre- 
viously boiled to expel all its dissolved air. In the opera- 
tion air should be excluded as much as possible to prevent 
the formation of carbonate. The salt in solution is not a 
definite compound, but consists of several oxyacetates in 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 229 

variable proportions. The reaction between the oxide and 
acetate is sometimes expressed in this wise: 3Fh{CJlfi^)^ 
+ 3PbO = Pb,0{C,H,OJ..Pb30,(C,H30J, 

GpULARD^s Extract is a term often applied to the solu- 
tion. It is a clear, colorless liquid of alkaline reaction, 
usually depositing a sediment after contact with air, which 
consists of carbonate. The solution is never used inter- 
nally; but externally it is preferred to a solution of the 
acetate. 

Diluted Solution of Lead Subacetate. Liquor Plumbi Sub- 
acetafis Dilutus. — Lead- WATER. — A solution of 3 parts Gon- 
ial d's extract in 97 of boiled water which has been cooled. 
The formation of opalescence in the solution is due to the 
carbonic acid gas in the water. It may be dispelled with a 
few drops of acetic acid. Lead-water has at times been 
mistaken for lime-water , and serious results have attended 
the mistakes. It has been suggested that the opalescence 
in lead water be allowed to remain, as a mark of distinc- 
tion from lime water, which should always be dispensed as 
a clear and transparent solution. Lead-water is used ex- 
ternally as a cooling and soothing application. 

Liniment of Lead Subacetate. — This sedative and cool- 
ing application to burns, which is a mixture of 40 parts of 
solution subacetate lead and 60 parts cottonseed oil, has 
been dismissed from the 1890 U. S. P. 

Cerate of Lead Subacetate. Ceratum Plumbi Subacetatis. — 
GouLARD^s Cerate. — Twenty parts of solution subacetate 
lead are incorporated with 80 parts of camphor cerate; the 
resulting preparation has the qualities of the solation in 
ointment form. The addition of a few drops of acetic acid 
prevents the cerate from becoming yellow. 

Lead-Plaster. Emplastrum Plumbi. — Diachylon or lead-plas- 



230 PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 

ter is a chemical compound, an oleate of lead, prepared by 
boiling together lead oxide and olive oil. Olive oil contains, 
among other fatty bodies, the oleate of propenyl, 03H^(Cja- 
HasOJg, which reacts upon the PbO thus: 2C3H,(0,,H330,) 
+ 3PbO + 3H,0 = 3Pb(C,3H330J, (oleate of lead or lead- 
plaster) -|- 2C3H^(OH)3 (glycerin). The lead-plaster is a 
by-product in the manufacture of glycerin. Lead-plaster is 
chiefly valuable as a base for many of the medicinal 
plasters. 

Diachylon Ointment. — Lead-plaster reduced to the 
consistency of an ointment with olive oil constitutes the 
diachylon ointment. It is perfumed with oil of lavender. 

Lead Nitrate. Plumbi Nitras. Pb(N03)2.— Lead nitrate 
is readily obtained by dissolving lad oxide in nitric acid 
by means of heat, filtering, evaporating and crystallizing: 
PbO + 2HNO3 = Pb(]Sr03), + H,0. It is in form of trans- 
parent or whitish, nearly opaque crystals, permanent in air, 
soluble in water, odorless, astringent taste. It is used 
mainly in making the lead iodide, though at times it is used 
externally. 

Lead Iodide. Plumbi lodidum. Pbl,. — A solution of lead 
nitrate is precipitated by a solution of a soluble iodide, 
potassium iodide usually, and the precipitate washed and 
dried. Pb(N03), + 2KI = Pbl, + 2KNO3. Lead iodide 
is a heavy, bright-yellowish powder, unchanged in air, 
odorless, tasteless, and practically insoluble in alcohol and 
water, but soluble in solution of ammonium chloride and 
in solution of the acetates of the alkalies. 

The iodide is sometimes given internally in doses of 
0.03 to 0.10 Gm., but it is chiefly used in form of oint- 
ment. 

Ointment of Lead Iodide. Unguentum Plumbi /odidi.—Ten 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 23l 

parts of lead iodide are incorporated with 90 parts of ben- 
zoinated lard to obtain the ointment of lead iodide. 

Lead Carbonate. Plumbi Carbonas. (PbC03),Pb(0H),.— 
White-Lead. — The carbonate is made on a very extensiv9 
scale for use as a pigment by exposing metallic lead to the 
action of the air, acetic acid vapors and decaying matter 
which yields carbonic acid gas. It may be made by preci- 
pitating a solution of lead nitrate with sodium carbonate, 
washing and drying the precipitate: Pb(N03)2 + Na^OOg 
= PbCOg + SNaXOg. It is not a true carbonate, but con- 
tains, as its formula indicates, a certain quantity of hydrox- 
ide. Its chief use is in the arts as a base for paints. In 
pharmacy it is used externally in form of ointment, and 
very often injudiciously in cosmetics and hair-restorers. 

Ointment of Lead Carbonate consists of 10 parts of lead 
carbonate and 90 of benzoinated lard thoroughly incorpo- 
rated ; it is used externally to reduce inflammation. 

Copper Salts. 

Copper is found in a native state, but it also occurs as 
oxide, sulphide, arsenate, carbonate, sulphate, etc. It is 
of a red color; specific gravity, 8.95 to 9, and is more valu- 
able in the arts and manufactures than in pharmacy. It 
is a dyad; atomic weight, 63.18; and it forms two official 
salts, the sulphate and acetate; symbol, Cu. 

Analytical Reactions. — 1. H^S produces a black pre- 
cipitate of the sulphide, CuS. 

2. Red cupric ferrocyanide is precipitated from copper 
solutions by ferrocyanide of potassium. 

3. Ammonia-water gives deep-blue color with dilute so- 
lutions of copper salts and a blue precipitate in strong 
solutions. 



232 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

4. Metallic zinc or iron is coated with copper in solutions 
of copper, an equivalent quantity of the zinc or iron going 
into solution. 

Copper Sulphate. Cupri Sulphas. CuSO^SH^O. — Blue Vit- 
riol PR Blue-stoi^e. — This salt is made on a large scale 
by dissolving waste copper in warm dilute sulphuric acid, 
evaporating, crystallizing and purifying by recrystalliza- 
tion. It is in form of large, translucent, deep-blue crys- 
tals, efflorescent, odorless, nauseous taste, soluble in water, 
insoluble in alcohol. Internally in doses of 0.30 G-m. it is 
emetic, in 0.03 Gm. doses tonic; externally its solution is a 
good stimulating wash. It is largely used as a disinfectant 
together with sulphate of iron. 

The impurities sometimes present are iron, alkalies and 
alkaline earths, lead, zinc and arsenic. 

Copper Acetate, Cu(C2H30„)2HoO. — Of several methods 
of preparing this salt, that in which lead acetate is em- 
ployed in solution with copper sulphate is the most conven- 
ient one: CuSO, + Pb(C,H,0,), = PbSO, + Cu(C,H30J,. 
The lead solution should be concentrated. The solu- 
tion of the acetate is filtered and allowed to crystallize, 
when it yields deep-green prismatic crystals which are 
odorless, efflorescent, soluble in water, and only slightly 
soluble in alcohol. The salt is sometimes, though errone- 
ously, called verdigris. It is used in much the same 
manner as the sulphate is, but is not any longer official. 

Mercury and Its Salts. 

Mercury, or quicksilver, is one of the only two liquid 
elements, bromine being the other, known to chemists. 
The sulphide, or cinnabar, HgS, is its most abundant 
natural compound, and from it usually by heating it in fur- 



PHARMACEUTICAL AN^D MEDICAL CHEMISTET. 233 

naces with access of air, the metal itself is obtained. The 
metal is volatile, and, becoming disengaged from the sul- 
phur, which burns and escapes as SO2 in the process, its 
vapors are conducted into suitable chambers and there 
condensed : HgS -j- 0^ = Hg -f SO,. There are other 
processes of extraction, but they are more complicated 
and little used. The extensive mines of California yield 
at present more than enough to supply the markets of 
this country, and considerable quantities are exported. 
There are very rich mines in Spain also which have 
been worked from pre-Christian times, and are still pro- 
ductive. 

The mercury salts are a very important class of com- 
pounds, pharmaceutically and chemically, but the chief 
and most extended use of the metal is found in the arts — 
in the manufacture of thermometers, barometers, mirrors, 
in mining gold and silver by amalgamation, and in mak- 
ing the pigment vermilion, etc. For pharmaceutical pur- 
poses the crude mercury is purified, preferably by distilla- 
tion, or by squeezing through chamois leather. The 
latter method removes only suspended matter or mechani- 
cal impurities, as traces of oxide or water. Mercury is a 
silver-white, bright, liquid metal, odorless, tasteless, in- 
soluble except in some acids; it is slightly volatile at ordin- 
ary temperatures; its volatility increases with the tempera- 
ture, being greatest at its boiling-point, 662° F., and least at 
its freezing-point, — 40° F. Mercury sometimes contains 
tin or other metals as impurities, and when it does, globules 
dropped upon white paper do not retain their globular 
form nor roll about freely, and frequently leave traces or 
streaks on the paper. The metal should have a bright 
surface and should be dry. 



234 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Mercury has an atomic weight of 200 (exactly, 199.80) 
and forms two series of compounds, the mercuwus and 
the mercuric. It is a dyad, and in the mercuric salts a 
single atom has bivalent value, while in the mercurous 
salts two atoms together have a combining value of two. 
The two chlorides will illustrate this by their graphic 
formulas : 



Mercuric Chloride, HgCla. 
.01 



H 



< 



01 



Mercurous Chloride, HgaCla. 
Hg-01 

Hg-01 



The base in the mercuric salts is always a single atom of 
mercury, Hg, while the base in the mercurows salts always 
consists of tvw atoms — Hg^. In the mercurous com- 
pounds one bond from 'each of two atoms of mercury neu- 
tralizes or combines with each other, leaving the one other 
bond from each atom to unite with a radical equivalent 
to two bonds. 

Important Reactions of Compounds of Mercury. 



Hydrochloric acid 

gives : 

Ammonia -water 
gives : 

Hydrogen sulpliide 
gives : 

Petassium iodide 
gives : 

Potassium hydrox- 
ide gives : 



With Mercuric Salts 
in Solution. 



No precipitate, HgClg 
soluble (corrosive 
sublimate). 

White precipitate (call- 
ed " white precipi- 
tate ") NHsHgCl. 

Black precipitate, HgS 
(sulphide). 

Red precipitate, Hglg 
(red mercuric iodide). 

Yellow precipitate, 
HgO (yellow oxide). 



With Mercurous Salts. 



White precipitate, in- 
soluble, Hg2Cl2 (cal- 
omel). 

Black precipitate, 
NH^Hg^Cl. 

Black precipitate, 
HgaS (sulphide). 

Green or yellow pre- 
cipitate, Hgala. 

Nearly black precip- 
itate, HgaO. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 335 

All the salts of mercury are poisonous, but the mercuric 
are far more so than the mercuro?^.^. There is no specific 
antidote for salts of mercury, but white of egg and other 
albuminous substances have proved of some value by coagu- 
lating the soluble salts of mercury when administered in 
time. Free use should be made of emetics or the stomach- 
pump, and eggs and milk given freely. 

A piece of bright copper or a bright penny (made so by 
dipping into nitric acid) becomes coated with mercury in 
solutions of mercury salts, an equivalent quantity of copper 
going into solution. 

Mercury dissolved in hot and concentrated nitric acid 
yields the mercuric nitrate, but if the nitric acid is diluted 
and cold, the oxidation is incomplete and the mercurous 
nitrate is formed. 

Preparations Containing Metallic Mercury. 

No other element is used so largely in the metallic state 
in medicine and pharmacy as mercury, and the United 
States Pharmacopoeia recognizes five such preparations. 

Mass of Mercury. Massa Hydrargyri. — Blue Pill or Blue 
Mass. — Mercury is rubbed or triturated with honey of 
rose and glycerin until globules are no longer visible under 
a magnifying glass of ten-diameter power — that is, until 
the metal is thoroughly subdivided and incorporated with 
the excipients. This work is laborious and tedious when 
executed with pestle and mortar, and resort is profitably 
had to machinery, especially when manufacturing it on the 
large scale, as is done at present. "When thorough subdivi- 
sion has been accomplished, powdered licorice and marsh- 
mallow are added to make a mass of a pilular consistence. 

This preparation contains 33 per cent of metallic mer- 



236 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

cury, and is usually given in doses up to 0.66 to 1.00 gm. 
as a purgative in bilious affections, its administration 
to be followed by a mild saline cathartic. 

Mercurial Ointment. Unguentum Hydrargyria — Blue Oint- 
MEKT. — Mercury is extinguished or killed, as the process 
of subdividing mercury by trituration is often called, with 
previously prepared mercurial ointment, or, as the 1890 
U. S. P. directs, with oleate of mercury, and incorporating 
with it melted lard and suet. This ointment is a conven- 
ient form for the external administration of mercury, and 
is largely used. It contains 50 per cent of mercury. 

Mercurial Plaster. Emp/astrum Hydrargyri. — This plaster 
is employed in medicine when it is not convenient to use 
the ointment. It contains 30 per cent of mercury extin- 
guished with oleate of mercury and incorporated with 
lead-plaster. 

Ammoniac Plaster with Mercury. Emplastrum Ammoniac 
cum Hydrargyro. — This plaster is somewhat milder than the 
above, containing only 18 per cent of mercury extin- 
guished with oleate of mercury, besides lead-plaster. The 
ammoniac is previously emulsified witli dilute acetic acid. 

Mercury with Chalk. Hydrargyrum cum Creta. Is a prepara- 
tion of metallic mercury in powder form, and serves the 
same purpose as the mass does. Mercury, clarified honey 
and chalk are triturated until the mercury is no longer 
visible under a ten-diameter lens, the trituration being 
facilitated by the addition of a small quantity of water. 
Lastly enough chalk is added to make the preparation con- 
tain 38 per cent strength of mercury, and the whole thor- 
oughly dried. The preparation should be kept in well- 
stoppered bottles protected from light to prevent the 
formation of traces of oxide of mercury. 



I 



PHARMACEUTICAL Al^r> MEDICAL CHEMISTRY. 237 

Salts of Mercury. 

The salts of mercury should be kept in dark, amber- 
colored, well-stoppered bottles, protected from light. 
When handling them it should be borne in mind that 
nearly all them are very poisonous. 

Corrosive Mercuric Chloride. Hydrargyri Chloridum Corrosivum. 
HgOl^.— Corrosive Sublimate, Corrosive Chloride of 
Mercury. — This, one of the most poisonous and valuable 
of the salts of mercury, is made from mercuric sulphate 
by subliming it with common salt — e.g., HgSO^ + 2E'a01 
= HgOl, + N%SO,. 

The HgSO^ is obtained from metallic mercury by boil- 
ing with strong sulphuric acid : 2H2SO4 + Hg = HgSO^ 
+ SO, + 2H,0. 

The corrosive chloride occurs in crystalline masses (to 
distinguish it from calomel, which is in powder form), is 
odorless, has persistent metallic taste, is permanent in air, 
soluble in water, alcohol and ether, and volatilizes when 
heated to a high degree, yielding vapors which are ex- 
tremely poisonous. 

Arsenic is sometimes detected as a contamination. Cor- 
rosive sublimate is one of the most powerful and exten- 
sively employed antiseptics. It has come into wide use of 
late in antiseptic surgery, proving the most valuable and 
powerful antiseptic and disinfectant in use. Its other 
medicinal applications are numerous. Internally it is very 
valuable as an alterative; its dose ranges from 0.001 to 
0.005 Gm. The serious consequences which may attend 
carelessness in the handling of this salt should prompt 
extreme caution in its use. 

Mild Mercurous Chloride. Hydrargyri Chloridum Mite. — SuB- 



238 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 
CHLORIDE OF MeRCURY, MiLD ChLORIDE OF MeRCURY, 

Calomel. — Merciirous sulphate, Hg^SO^, mixed with com- 
mon salt and heated, produces a sublimate of the mercu- 
rous chloride: Hg.SO, + 2NaCl = Hg.Cl, + Na.SO,. The 
mercuric sulphate when rubbed with another atom of 
mercury becomes the mercurous sulphate: HgSO^ -f Hg 
= Hg,SO, ^ 

The sublimate of calomel is obtained in powder form 
by rapid and sudden cooling of the vapors; slower cooling 
yields the sublimate in mass form. Calomel, the Hydrar- 
gyri Chloriclum Mite of the Pharmacopoeia, is in form of a 
white, heavy, impalpable powder [Hydrargyri Chloridum 
Cor?^osivum is kept in form of crystalline masses), and is 
odorless, tasteless, wholly insoluble in ordinary solvents, 
and quickly blackened by ammonia- water. It is ^^er- 
manent in the air, but volatilizes at high temperatures; it 
may be reduced to metallic mercury by heating with dried 
sodium carbonate in a long test-tube. 

On account of the similarity in the processes for making 
both the mild and corrosive chloride, the former may con- 
tain traces of the latter, a possibility which must be 
strenuously guarded against. Mercuric chloride may be 
detected in calomel by washing the latter with alcohol or 
ether, which dissolves out any corrosive chloride that 
might be present, and testing the filtrate for chloride with 
solution silver nitrate, and for mercury with H^S. Calo- 
mel is totally insoluble in ordinary solvents, and water or 
alcohol, after having been agitated with it, should remain 
unaffected by any reagent. 

Ammoniated Mercury, which resembles calomel in 
appearance, is soluble in acetic acid, from which solution it 
may be precipitated as the black sulphide with H^S gas. 



PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 239 

The last three tests should be applied before putting the 
calomel upon the dispensing-counter. 

Owing to its insolubility in the system its action is largely 
mechanical, and its dose comparatively large, ranging from 
.030 to 1.00 Gm. In small doses, from .006 to .030 Gm., 
it is alterative and stimulating to the liver; in large doses 
purgative. It was at one time believed that sodium chloride 
converted calomel partly into corrosive sublimate, but ex- 
tensive investigation and trials have failed to verify this. 
The pharmacist should nevertheless be vigilant to prevent 
its being dispensed with salts concerning whose chemical 
action toward it there may be a doubt. Calomel entei's 
into the Compound Antimony Pills, and into the Compound 
Cathartic Pills. 

Red Mercuric Iodide. Hydrargyri lodidum Rubrum. Hgl^. — Ebd 
Mercuric Iodide, Bin'iodide of Mercury. — Obtained 
by adding potassium iodide to mercuric chloride in solu- 
tion, and thoroughly washing and drying the precipitate at 
a low temperature. The decomposition is represented by 
the following equation : HgCl, + 2KI = Hgl, + 2KC1. 
As the red iodide is soluble in excess of potassium iodide 
solution, care should be taken to avoid an excess. It is a 
scarlet-red crystalline powder, odorless, tasteless, almost in- 
soluble in water, slightly soluble in alcohol and permanent 
in the air. Water shaken with the salt should not be 
affected by solution of nitrate of silver — test for the absence 
of soluble iodide or chloride. 

Mercuric iodide in medicine is given internally chiefly 
as an alterative in syphilis; dose, .002 to .015 Gm. 

Yellow Mercurous Iodide. Hydrargyn lodidum Flavum. Hg J^- 
Green Mercurous Iodide, Protoiodide of Mercury. — 
Iodine and mercury are rubbed together in equivalent 



240 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

quantities in presence of alcohol, and when combination is 
completed washed with alcohol. The alcohol prevents by 
its evaporation the elevation of temperature which the 
chemical union induces ; alcoliol is employed to wash 
the finished salt because it dissolves out the traces of mer- 
curic iodide which are usually formed, and which are 
much more poisonous than the mercurous iodide : Hg^ + 1^ 
= Hgjj- '-The JJ. S. P. directs the salt to be made by 
precipitating mercurous nitrate solution by potassium 
iodide solution: Hg,(N03), + 2KI = HgJ, -f 2KNO3. 

The green or yellow iodide is so called because it has a 
greenish-yellow color; it becomes quite yellow when ex- 
posed to air, wherefore it is termed yellow iodide in the 
17. S. P. It is practically insoluble in water, insoluble in 
alcohol, odorless, tasteless, and becomes darker in color if 
exposed to light for a long time. 

The medical properties of the yellow iodide are the same 
as those of the red, but because of its milder action it is 
sometimes preferred to the latter salt. The dose is some- 
what larger, being often given in doses of .065 Gm. 

Yellow Mercuric Oxide. Hydrargyri Oxidum Flavum. HgO. — 
Made by adding solution of mercuric chloride to solution 
of soda and setting aside for several hours, when the pre- 
cipitate formed is thoroughlj'' washed with distilled water 
and dried between blotting-paper: HgCl^ -j- 2NaOH = 
HgO + 2Na01 + H,0. 

Yellow mercuric oxide is a light, orange-yellow powder, 
becoming darker when exposed to light, insoluble in water, 
tasteless and odorless. It has the same composition as the 
red oxide. It is chiefly used for the ointment and for the 
oleate of mercury. 

Ointment of Yellow Mercuric Oxide. Unguentum Hydrargyri 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 241 

Oxidi Flavi. — Contains 10 parts of the yellow oxide thor- 
oughly incorporated with 90 of simple ointment. It and 
the ointment of red oxide mercury are used medicinally in 
similar indications. 

Oleate of Mercury. 0/eatum Hydrargyri. — Made by dissolving 
20 parts of yellow mercuric oxide in 80 of oleic acid. Chem- 
ical combination takes place as follows: HgO-l-2HCjaHg302 
(oleic acid) = ^g{Q^Jl^fi^^ (oleate mercury) -\- H^O. Heat 
should not be employed. The oleate is employed when it 
is not convenient to use the ointment. 

When kept for some time metallic mercury separates, 
hence the preparation should never be kept long. 

Red Mercuric Oxide. Hydrargyri Oxidum Rub rum. HgO. — 

Mercuric Oxide, Red Precipitate. — This oxide differs 
from the yellow probably only in color ; chemically it is the 
same. It may be made by decomposing mercuric nitrate 
with heat, e.g. : 2H,(N03) 2 + heat = 2HgO + 4^0, + 0,. 

The salt is usually in heavy, orange-red crystalline pow- 
der, sometimes in scales, odorless, tasteless, insoluble in alco- 
hol and water, soluble in nitric or hydrochloric acid. It 
differs from the yellow oxide in not forming a mercuric 
oxalate of a white color, as that does, when digested on 
water bath with solution of oxalic acid. 

Ointment of Red Mercuric Oxide. Unguentum Hydrargyri Oxidi 
Rubri. — This ointment is the principal form in which the 
red oxide is used. It contains 10 per cent red oxide rubbed 
smooth with castor oil and incorporated with simple oint- 
ment; it is much employed by ophthalmologists and derma- 
tologists, and is popularly known as red precipitate ointment. 
It should not be dispensed except upon a physician's order. 

Mercuric Cyanide. Hydrargyri Cyanidum. HgCy^ or Hg(CN3). 
—This salt of mercury is prepared by passing hydrocyanic 



242 PHARMACEUTICAL AND MEDJCAL CHEMISTRY. 

acid gas into mercuric oxide: HgO + ^HCN = Hg(CN)2 
-j- H^O. The hydrocyanic acid is made in the process by 
the action of sulphuric acid upon ferrocyanide of potassium. 

The cyanide occurs as colorless or white prismatic crys- 
tals darkening on exposure to light; it is odorless, of a 
bitter taste, soluble in alcohol and water, and exceedingly 
poisonous. It should be tested for mercuric chloride with 
iodide of potassium. It is alterative; dose, .003 to .005 Gm. 

Ammoniated Mercury. Hydrargyrum Ammoniatum. Hg^H^Ol. 
— White Precipitate, Mercur-ammonium Chloride. 
— Obtained by adding solution of mercuric chloride to am- 
monia-water and washing and drying the precipitate: 
2NH,H0 + HgOl, = NH^Ol + HgNH.Cl + 2H,0. There 
are numerous mercur-ammonium compounds, but the 
official one probably is as above. White precipitate occurs 
in form of white powder, odorless, tasteless, insoluble in 
alcohol or water, and permanent in air. It is very poisonous, 
and care should be taken not to mistake it for calomel, 
which resembles it in appearance and physical properties. 

Ointment of Ammoniated Mercury. Unguentum Hydrargyri Am- 
moniati. — Ammoniated mercury is never used internally, 
and only seldom externally in form of ointment. The oint- 
ment contains 10 parts ammoniated mercury and 90 of 
benzoinated lard, and is employed in various skin-diseases. 

Yellow Mercuric Sulphate. Hydrargyri Subsulphas Flavus. 

Hg(HgO),SO, or HgSO,2HgO.— Turpeth Mineral, Ba- 
sic Sulphate Mercury. — Mercuric sulphate prepared as 
above shown is added to boiling water, when the yellow 
basic sulphate separates as a precipitate, while some acid 
mercuric sulphate which is formed remains in solution. 

Turpeth mineral is a heavy, lemon-yellow powder, odor- 
less, tasteless, insoluble in water and permanent in air. It 



PHARMACEUTICAL AN"D MEDICAL CHEMISTRY. 243 

should be free from mercurons salt. If this is absent the 
salt is soluble in 20 parts of hydrochloric acid. The salt is 
rarely used — occasionally it is given as an emetic, in doses 
of .065 to .195 Gm., to children suffering from croup. 

Red Mercuric Sulphide. HydrargyH Sulphidum Rubrum. HgS. 
— Mercuric Sulphide, CiiTNABAr., Vermilion^. — Mer- 
cury and sulphur are fused and the mass powdered and 
sublimed. Much of the finest vermilion in commerce comes 
from China, though some is made in this country. It is a 
brilliant, dark-red or scarlet powder, odorless, insoluble, 
and permanent in the air. It is used most extensively in 
the arts as a pigment; in medicine it is used but little, and 
is not any longer oflficial. 

Solution of Mercuric Nitrate. Liquor H yd rargyri Nitraiis. — A 
liquid containing 60 per cent of mercuric nitrate, Hg(N03)2, 
together with about 11 per cent of free nitric acid. It is 
made by dissolving red oxide of mercury in diluted nitric 
acid. It is a clear, colorless liquid of a specific gravity of 
2.10, miscible with alcohol or water. The solution is very 
corrosive and poisonous, and is employed principally in 
the treatment of ulcers and malignant growths as a cau- 
terant. 

Citrine Ointment of Mercuric Nitrate. Unguentum H yd rargyri 
Nitratis. — CiTRiNE OiNTMENT. — Made by thoroughly incor- 
porating solution of mercuric nitrate with a mixture of lard 
oil and nitric acid. It is employed externally in skin 
diseases and in some diseases of the eyes. 



244 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 



The Silver Salts. 

Silver occurs chiefly in the metallic state in nature, but 
its sulphide is also found abundantly either alone or asso- 
ciated with sulphide of lead. The chloride, horn-silver, is 
also found in large enough quantities to make it profitable 
to extract the silver. Silver is of a brilliant whiteness, very 
malleable and ductile, and used in pharmacy principally in 
making the nitrate, from which, in turn, all the other 
official salts are prepared. It has a specific gravity of 10.5, 
and is applied to a great variety of purposes in the arts. 
Coin-silver contains copper to give it greater hardness. 
Silver is a monad and has an atomic weight of 107.66; sym- 
bol, Ag {arge7itu7n). Metallic silver in form of silver-leaf 
is used by pharmacists for coating pills. 

The silver salts should be kept in well-stoppered bottles 
protected from light. 

Analytical Eeactioks. — 1. Silver is soluble in nitric 
acid, forming the nitrate, with the evolution of '^fi^ vapors. 

2. Chlorides in solution produce a curdy white precipi- 
tate of silver chlorine, which is insoluble in nitric acid, but 
readily soluble in excess of ammonia-water. 

3. The alkalies give a brownish precipitate of silver oxide. 
This precipitate should be handled carefully, as it easily 
explodes when rubbed in contact with readily oxidizable 
substances. 

4. Metallic silver is blackened by hydrogen or ammonium 
sulphide, and solutions of silver salts give black precipitates 
with the same reagents. 

5. Solutions of silver salts in contact with the skin turn 
the latter black, owing to the reduction of silver to the 
metallic state. 



I 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 245 

Silver Nitrate. Argenti Nitras. AgNOg. — This, the most 
valuable of the silver salts^ is made by dissolving pure 
silver (not coin-silver, which contains copper) in nitric 
acid, evaporating to dryness, and increasing the heat 
until the mass melts to expel all nitric vapors. When 
cooled the mass is dissolved in water and crystals allowed 
to form in the filtered solution. Any copper which may 
have been present is thus oxidized and remains on the fil- 
ter. 3Ag, + 8HNO3 = 6AgN03 + N,0, + 4H,0. The 
nitrate is in form of heavy tubular, transparent, colorless 
fusible crystals, soluble in Avater, odorless, of metallic taste, 
and becoming gray or black upon exposure to light in 
contact with organic matter. Metallic im^nirities are 
detected by removing all the silver with hydrochloric acid 
and evaporating the filtrate to dryness — a fixed residue 
would indicate the presence of other metals. Sodium 
nitrate is sometimes thus detected, and if present is usually 
an adulteration. Copper, if present, gives blue solution 
with ammonia- water. Silver nitrate is used externally 
as a caustic and escharotic. Great care should attend its 
internal administration, as it is very poisonous. 

Antidote. — Common salt produces the insoluble silver 
chloride : AgNO, + NaCl = AgCl + NaNOg. Emetics 
should follow. 

Fused Silver Nitrate. Argent/' Nifras Fusus. AgNO^ + AgCl. 
Lunar Caustic. — Made by melting silver nitrate crystals 
at as low a temperature as possible and adding 4 per cent 
of hydrochloric acid, heating until the nitric vapors are dis- 
pelled, and casting into moulds. The HCl produces AgCl, 
which, though insoluble, renders the nitrate much less brittle 
and more tenacious. The fused or moulded silver nitrate is 
in form of hard, white, solid pencils, having the same proper- 



246 PHAKMACEUTICAL AND MEDICAL CHEMISTRY. 

ties tliat the crystals have, excepting that it is not wholly 
soluble in water, the chloride, amounting to about 5 per 
cent., remaining undissolved. 

Diluted Silver Nitrate. Argent/ Nitras Dilutus. AgNO^ -f 
KNO3. — Diluted or mitigated silver nitrate is made by 
melting together equal parts of silver and potassium 
nitrates in a porcelain crucible and pouring into moulds. 

This preparation is used whenever a milder caustic than 
the pure silver nitrate is desired. Its properties are the 
same as those of the undiluted nitrate, only less power- 
ful. 

Silver Cyanide. Argenti Cyanidum. AgCN. — Obtained by 
adding solution of potassium cyanide to solution of nitrate 
of silver : KgSO, + KCN = AgCN + KNO3. The potas- 
sium nitrate formed is removed by filtration and the wash- 
ing of the precipitate. 

The salt is a white, insoluble powder, permanent in dry 
air, and becoming brown or black by exposure to light and 
organic matter. It may also be made by passing hydro- 
cyanic gas into solution of silver nitrate. 

Its sole use is in the extemporaneous preparation of hy- 
drocyanic acid, which is made by bringing together pre- 
scribed quantities of silver cyanide, hydrochloric acid and 
water, allowing the precipitated silver chloride to sub- 
side, when the solution of the acid is poured off. The 
latter constitutes the official hydrocyanic acid, which con- 
tains 2 per cent. HON. This acid is classed among the 
organic acids. 

Silver Oxide. Argenti Oxidum. Ag^O. — A solution of silver 
nitrate is treated with caustic potassa solution, and the 
precipitate thoroughly washed and dried : 2AgN03 + 
2K0H - Ag^O + 2KNO3 4- H,0. Silver oxide is a heavy. 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 247 

nearly black, and almost insoluble powder. When tritu- 
rated with organic or easily oxidizable bodies it is liable to 
cause explosion, owing to the readiness with which it parts 
with its oxygen. It should not be brought in contact with 
ammonia. Pills of the oxide frequently explode. 

Silver Iodide. Argent! lodidum. Agl. — Potassium iodide 
and silver nitrate produce silver iodide and potassium 
nitrate. AgNOg -f KI = Agl + KNO3. The iodide is a 
light, yellow powder, insoluble, odorless and tasteless. If 
pure it is not changed by light, but it generally turns 
greenish-yellow in time. 

Iron and its Salts. 

Iron furnishes a greater number of official salts and 
preparations than any other metal, and its salts are among 
the most important in pharmacy and medicine. It is 
hard, tenacious, ductile, malleable, grayish white, specific 
gravity 7.76, and oxidizes in moist air. Iron can be 
made to burn in oxygen. It unites with most of the metals 
and non-metals, forming two classes of compounds, the 
ferrous and the ferric. In the former it has two bonds 
and in the latter four but only three are capable of unit- 
ing with bonds of other elements. For illustration : 

/Ol 

Ferrous chloride, FeCL or Fe^ 

^01 

The iron has two bonds. 

Fe^Cl 
Ferric chloride, Fe.Cl, or ! q} 

Fe^Ol 

\oi 



248 PHAEMACEUTICAL Ai^D MEDICAL CHEMISTRY. 



Here one atom of iron has four bonds, but one from 
eacli of two atoms combines with or neutralizes each other, 
so that huo atoms together have six bonds which will unite 
with the bonds of other elements. Atomic weight, 56. 
Symbol, Fe {ferrum). 

Sources. — Iron occurs very abundantly and is widely 
distributed in nature. Native iron is only found in me- 
teors or shooting stars. The chief sources of iron are fer- 
ric oxide, Fe^Og , and magnetic oxide, Fe304(or FeO-Fe^Og), 
both of which occur in a variety of forms; the carbonate, 
FeCOg , and the sulphides, of which there are also a great 
variety, from the FeS to the Fe,Sg. The sulphate and 
phosphate are also found. 

Important Analytical Reactions of Iron Salts. 



Reagent. 



Ferrocyanide 
potassium, 
K4FeCy6. 



Ferricyanide 
potassium, 
KsFeCye, o r 

KeFe^Cyia. 



Ammonia-water, 
NH4OH. 



Ammonium sul- 
phide, (NH4)2S. 



Sulphocyanide 
potassium, 
KCyS. 

Tannic acid. 



With Ferrous Salts. 



Potassium feirous-ferrocya- 
nide, KsFeFeCye. Nearly 
white, turning blue in air. 
Everitt's salt. 

Ferrous ferricyanide, 
Fe3(FeCy6)2. Dark blue. 
Turnbull's blue. (This is 
a very valuable test for 
detecting ferrous in ferric 
salts.) 

Ferrous hydroxide, Fe(0H)2. 
White, turning through 
green, etc., to brown, be- 
coming ferric. 

Ferrous sulphide, FeS. Black 
precipitate. 



No change. 

No change at once. 



With Ferric Salts. 



Ferric ferrocyanide 
precipitate, F e 4 - 
(FeCye)^. Deep 
blue color, Prus- 
sian blue. 

No precipitate, but 
greenish color. 
Fe2(FeCy6)2. 



Ferric hydroxide, 
Fe2(OH)6, brown 
magma. 

Ferrous sulphide, 
FeS, black precipi- 
tate. The ferric 
becomes reduced to 
ferrous salt. 

Intensely red solution 
of ferric sulphocy- 
anide, Fe,(CyS)6. 

Blue-black precipi- 
tate of ferric tan- 
nate. 



I 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 249 

In the study of the long list of iron salts it is again con- 
venient to follow the order of derivation, as given below : 

First Series. 
Iron, metallic. 

Iodide, saccharated. 
Iodide, syrup. 
Lactate, salt. 
Chloride, salt. 
Chloride, solution. 
Chloride, tincture. 

Acetate iron and ammonium. 
Sulphate, crystals. 

Second Series. 

Sulphate, precipitated. 
Sulphate, dried. 

Pills aloes and iron. 
Carbonate, saccharated. 
Carbonate, mass. 
Carbonate, pills. 

Keduced iron. 
Iodide pills. 

Compound iron mixture. 
Hypophosphite, salt. 
Subsulphate, solution. 
Tersulphate, solution. 

Third Series. 
Sulphate iron and ammonium, double salt. 
Valerianate, salt. 

Hydrated oxide of iron and magnesia. 
Hydrated oxide, magma. 



250 PHABMACEUTICAL AI^D MEDICAL CHEMISTRY. 

Fourth Series. 

Hydrated oxide, dried, troches. 
Hydrated oxide, dried, plaster. 
Acetate, solution. 
Nitrate, solution. 

Tartrate iron and ammonium, scales. 
Tartrate iron and potassium, scales. 
Citrate, solution. 
Citrate, scales. 

Phosphate, soluble, scales. 

Phosphate iron, quinine and strychnine, 
syrup. 
Pyrophosphate, soluble, salts. 
Citrate iron and quinine, scales. 
Citrate iron and quiDine, scales, soluble. 
Citrate iron and ammonium, scales. 
Citrate, wine. 

Citrate iron and quinine, wine. 
Citrate iron and strychnine, scales. 

By reference to the above arrangement it will be seen 
that metallic iron furnishes directly or indirectly by deri- 
vation all the salts and preparations of iron mentioned in 
the U. S. P. The salts or preparations, or both, in each 
series are made directly from the salt or preparation lowest 
in the column above. Thus, for illustration, the solution 
of the nitrate is made from the hydrated oxide, which is 
prepared from the solution of the tersulphate; the latter 
in turn is derived from the crystals of the sulphate, and 
the sulphate from metallic iron. Or, in other words, 
among the series made directly from iron, the sulphate 
is the starting-point for a second series, of which the 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 251 

solution of the tersulphate yields a third series, among 
which is the hydrated oxide, from which the fourth series of 
salts and preparations, including all the scale salts, is made. 

Iron. — The United States Pharmacopoeia directs that 
metallic iron should be in the form of fine, bright and non- 
elastic wire, that form being usually very pure. 

Saccharated Ferrous Iodide. Ferri lodidum Saccharafum. 
Fel^. — Iron and iodine are made to react upon each 
other in presence of water : Fe2 + 21^ = 2Fel2. The green 
solution of the ferrous iodide is filtered into sugar of milk, 
and the mixture evaporated to dryness, triturated with 
more sugar of milk and a little reduced iron, and afterward 
preserved in small well-stoppered bottles in a dark and cool 
place. 

The object of adding the sugar of milk is to preserve the 
iodide, which is ordinarily very unstable, decomposing 
easily and becoming colored by the free iodine. The re- 
duced iron aids in preventing the separation of iodine. 
Sugar is employed for its preservative properties in a num- 
ber of other iron preparations, as will presently be seen. 
The saccharated iodide of iron is a yellowish-white, some- 
times grayish- white powder, dissolving to a clear solution 
in water. A brown color would indicate the presence of 
free iodine and preclude its employment for dispensing pur- 
poses. Free iodine when present may easily be detected 
by adding a few drops of gelatinized starch to the aqueous 
solution — a blue color would indicate its presence. 

Medicinally the saccharated iodide is used as an alterative 
and tonic. Dose, 0. 30 gm. It contains 20 per cent Fel,. 

Syrup of Ferrous Iodide. Syrupus Ferri hdidi. Fel^. — The 
syrup is made as the above, excepting that instead of add- 
ing to the solution of ferrous iodide sugar of milk and 



252 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

evaporating to dryness, simple syrup is added, yielding a 
preparation having all the properties of the dry saccha- 
rated iodide in a liquid state. The syrup should be kept 
exposed to daylight to aid the sugar in preventing the 
separation of iodine. If iodine does separate, it combines 
with the water in presence of daylight to form the colorless 
hydriodic acid, thereby avoiding the formation of a brown 
color. Syrup of ferrous iodide has a greenish color, and 
should not be dispensed if of a brownish color. Its dose is 
10 to 15 drops, largely diluted with water, to prevent its 
action upon the enamel of the teeth, which it invariably 
destroys when in contact for even a short time. The syrup 
contains 10 per cent, ferrous iodide; specific gravity about 
1.353. 

Ferrous Lactate. Ferri Lactas. Fe(C3H,03),.3H,0.— This 
ferrous, salt results when iron is dissolved in lactic acid: 
Ee,+4HC3H,03 = 2Fe(03H,03),+ 2H,. Whenever metallic 
iron is dissolved in an acid hydrogen is evolved. The solu- 
tion of the lactate is evaporated and allowed to crystallize, 
when the salt is obtained as a pale greenish-white crystal- 
line mass, or, if granulated, in grains. It is soluble in 
about 40 parts of water, is odorless and has a mild ferru- 
ginous taste. Medicinally it is used by some in preference 
to the other forms of iron, as it is believed to be more 
readily assimilated. Dose, 0.06 to 0.180 Gm. 

Ferric Chloride. Ferri Chloridum. Fe^Cl,.12H,0.— Obtained 
by dissolving iron in hydrochloric acid and oxidizing the 
ferrous chloride so produced to the ferric state with nitric 
acid, evaporating to dryness, expelling all acid vapors and 
crystallizing. 

When iron is acted upon by HCl, the ferrous chloride is 
produced: Fe, + 4HC1 = FeCl, + 2H,. The latter is oxi- 



PHARMACEUTICAL Al^D MEDICAL CHEMISTRY. 253 

dized to ferric chloride with nitric acid in the presence of 
more hydrochloric acid. The oxidation may be thus ex- 
pressed : 6Fe01, + 2HNO3 + 6HC1 = 3Fe,Cl, + N^O, + 
4H2O. Here again it will be well to remember that when 
nitric acid acts as an oxidizing agent, two molecules of it 
split up into H^O, ^fi^ and 30, and that the oxygen re- 
moves in this case the hydrogen from hydrochloric acid, 
leaving the chlorine free to unite with the ferrous chloride. 
The three atoms of oxygen require six of hydrogen to form 
water, hence the necessity of taking six molecules of HOI ; 
the six free hydrogen atoms require six molecules of FeOl, 
to convert them into Fe^Olg, because one molecule of Fe^Ol^ 
requires two more atoms of 01 than two molecules of FeOl^ 
or Fe^Ol^. If two atoms of chlorine oxidize two molecules 
of FeOl, into Fe^Olg, the six free hydrogen atoms will re- 
quire three times two FeOl^, or six FeOl^. The '^fi^ 
escapes in form of reddish fumes, and the one molecule of 
water from the 2HNO3 added to the three obtained from 
the six hydrogen atoms from six HOI and the three oxygen 
atoms from two HNO3 give the four molecules of water, 
balancing the equation. 

Ferric chloride is in yellow crystalline pieces, very deli- 
quescent and hence very soluble in water, also in alcohol 
and ether. It has an acid reaction, owing to presence of 
hydrochloric and sometimes nitric acid. Zinc and copper 
and the fixed alkalies are sometimes present as impurities, 
together with ferrous salt and oxychloride. Test solution 
of ferricyanide of potassium does not give a blue color in 
absence of ferrous chloride. This salt is rarely used inter- 
nally, the tincture being preferred. Externally it is used 
as a styptic. 

Solution of Ferric Chloride. Liquor Ferri Chloridi. Fe^Olg. — 



254 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

If in making the precedinpj the solution of Fe^Olg is not 
evaporated, but so adjusted by the addition of water that 
it contain 37.8 per cent of the anhydrous ferric chloride, 
the solution of ferric chloride will be the result. It is a 
reddish-brown liquid, of strongly acid reaction, styptic 
taste, specific gravity 1.387, miscible with water, alcohol 
and ether in all proportions. It is used principally to 
prepare the extensively used tincture chloride iron. 

Tincture of Ferric Chloride. Tinctura Ferri ChloHdi. Fe^Olg. 
— This preparation is made by diluting solution of ferric 
chloride with alcohol and allowing to stand for at least three 
months before using. It is made so long before using to 
permit the formation by the action of the free acid present 
upon the alcohol of certain compound ethers, among 
which the ethyl chloride predominates. These ethers are 
believed to have diuretic properties and a peculiar influ- 
ence upon the urinary passages. Sometimes a brownish 
precipitate of ferric oxychloride forms upon standing or 
upon dilution. This is due to not employing enough hy- 
drochloric acid in the preparation of the solution. The 
tincture is a clear, brownish liquid of an ethereal odor, 
styptic taste and acid reaction, and contains about 13.6 per 
cent of the anhydrous salt. It is the most important liquid 
preparation of iron. Dose, from 5 to 30 drops, largely 
diluted with water. 

Solution of Iron and Ammonium Acetate. Liquor Ferri et 
Ammonii Acetatis. Fe2(02ll30 Jg.NH^Cl.— Basham's MIXTURE. 
— Tincture of chloride of iron is added to solution of 
ammonium acetate containing excess of acetic acid ; 
mutual decomposition takes place according to the reac- 
tion, Fe.Ol, + 6NH,C,H30, - Fe,(0,H30,)3 + 6NH,C1. 
The solution is flavored with aromatic elixir and glycerin 



PHARMACEUTICAL AND MEDICAL CHEMISTKT. 255 

and water added. This solution should be freshly prepared 
when needed. 

The not unpleasant taste and its agreeable appearance, 
as well as its acceptability to the stomach, recommend 
it to a wider employment. Its dose is from 15 to 30 cc. 

Ferrous Sulphate. Ferri Sulphas. 'EQ^O^.lIifi. — Greei^ 
Vitriol. — This is the last in the series of salts made di- 
rectly from iron; it is obtained on the large scale by 
dissolving old scrap-iron in waste sulphuric acid, and puri- 
fying as far as possible by repeated crystallization. This 
form is usually employed for disinfecting and for other 
purposes which are not pharmaceutical. For pharma- 
ceutical purposes it should be made from the purest acid 
and iron wire. The following equation expresses the reac- 
tion: 2Fe, -f 2H,S0, = 2FeS0, + 2H,. Ferrous sulphate 
remains in solution, from which it is obtained by evapora- 
tion and crystallization. 

The salt occurs as large pale-green monoclinic prisms, 
efflorescing and becoming oxidized on exposure to air. It 
is odorless, has acid reaction, and is soluble in water but 
insoluble in alcohol. The crystals when heated melt in 
their water of crystallization. The impure salt, known in 
commerce as copperas, though it contains no copper, is 
used for disinfecting purposes. 

Granulated Ferrous Sulphate. Ferri Sulphas Granulatus. 
FeSO^.TH^O.— The crystals of sulphate of iron are dis- 
solved in water containing a little sulphuric acid and the 
solution poured into alcohol. The sulphate is insoluble in 
even dilute alcohol and precipitates in form of a granular 
powder; some of the impurities present in the crystals are 
soluble in alcohol, hence this method of precipitation 
yields conveniently not only a granular salt, but also a 



256 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

very pure one. It is a pale-green powder less liable to 
oxidize in the air than the crystals and better adapted for 
dispensing purposes than the latter. Otherwise it is iden- 
tical with the crystals. 

Dried Ferrous Sulphate. Ferri Sulphas Exsiccatus. FeSO^.- 
H,0. — A convenient quantity of the powdered crystals of 
sulphate of iron is exposed to heat until it ceases to lose 
weight, ascertained by weighing at intervals of 30 to 40 
minutes. This process yields a form of sulphate of iron 
containing only 1 molecule of water of crystallization, 6 
being dispelled by the heat. It is a grayish-white powder 
and is used for making pills, or whenever the crystals are 
unfit for use on account of either their bulk or water of 
crystallization. The dried sulphate represents nearly twice 
as much anhydrous salts as the crystals do. 

Pills Aloes and Iron. Pi/ufcB Aloes et Ferri. — These pills 
contain each 1 grain of dried sulphate of iron and 1 grain 
of purified aloes, besides the excipients, aromatic powder 
and confection rose. 

Saccharated Ferrous Carbonate. Ferri Carbonas Saccharatus. 
FeOOg. — Sulphate of iron crystals are made to react upon 
sodium bicarbonate and the precipitate of ferrous car- 
bonate thoroughly washed. The drained precipitate is 
mixed with finely powdered sugar and the whole dried on a 
water-bath: FeSO, + 2NaHC03 = FeCOg + ]Sra,SO,+ CO, 
-|- HjO. Here again the sugar acts as a preserving agent, 
preventing the decomposition and oxidation of the car- 
bonate, which ordinarily is not stable. It is a grayish 
powder, odorless, partially soluble in water, and wholly 
soluble in hydrochloric acid with copious evolution of 00^ 
gas. If the precipitate is not thoroughly washed, traces of 
sulphate will remain. These can be detected by test solu- 



\ 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 257 

tion of chloride of barium, which gives white precipitate 
in presence of sulphates. 

The carbonate is a ferruginous tonic; dose, 0.180 to 
1.33 Gm. 

Mass of Ferrous Carbonate. Massa Ferri Carbonatis. FeCOg. 
— This preparation was formerly known as Pilula Ferri 
Carbonatis because it is usually employed in making pills, 
its consistence fitting it especially for that purpose. Sul- 
phate of iron and sodium carbonate react upon each other, 
thus: FeSO, + Na.COg = Na^SO, + FeCOg. The pre- 
cipitate is thoroughly washed and incorporated with sugar 
and honey to form a mass of a pilular consistence. Mass of 
carbonate of iron is popularly known as Vallefs Mass. 
Dose, 0.33 Gm. 

Reduced Iron. Ferrum Reductum. Fe^. — Subcarbonate or 
hydroxide of iron is heated or calcined until it is reduced 
to the oxide Fe^Og and this is then reduced to the metallic 
condition by passing hydrogen gas over it. The reactions 
Fe,(0H)3 + heat = Fe.Og + 3H,0, Fe.Og + 3H, = Fe, 
+ 3H2O explain the process. 

It is a very fine black powder, wholly soluble in sul- 
phuric acid, and should contain not less than 80 per cent of 
metallic iron. It will burn in air, becoming the ferric oxide : 
2Fe2 + 3O2 = 2Fe203, the chemical process being the same 
as rusting, only much more rapid and illustrative of the 
chemical affinity between the iron and the oxygen of the 
air. The finely divided iron exhibits a greater surface to 
the action of the oxygen, and the chemical action is conse- 
quently so intense as to produce heat and flame. 

Keduced iron is one of the most valued of the chalybeate 
tonics; it is given in doses of 0.120 to 0.330 Gm. in pill 
form. 



258 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Pills of Ferrous Iodide. PHuIcb Ferri lodidi. Fel^. — These 
pills are made by acting upon reduced iron with iodine, 
and adding to the filtered solution of the resulting iodide 
of iron, powdered sugar, licorice root, licorice extract and 
acacia, and evaporating the mixture until it attains a 
pilular consistence, when it is divided into pills. To 
prevent the iodine from becoming liberated and the iron 
from oxidizing, the Pharmacopaeia directs that the pills 
should be coated with tolu balsam, which is dissolved for 
the purpose in stronger ether. The pills are rolled in this 
solution and allowed to dry. The ether evaporates very 
quickly, leaving a thin, impervious and air-tight coating of 
balsam upon the pills. 

Compound Iron Mixture. Mistura Fern Composita. FeOO, 
+ K^SO^. — Potassium carbonate is mixed with powdered 
myrrh, sugar, spirit of lavender to flavor, and rose- 
water, to which mixture, contained in a bottle in which 
the preparation is intended to be kept, coarsely powdered 
sulphate of iron is added, and the whole well shaken: 
FeSO, + K.COg = FeOOg + K^SO,. The mixture should 
be freshly prepared when wanted. It contains the sul- 
phate of potassium, which is formed, in addition to the 
carbonate, wherein it differs from the mass of carbonate of 
iron and the pills of iodide of iron, in each of which the 
formed sulphate is washed out and does not remain in the 
preparation. The mixture is similar in this respect to the 
compound pills of iron. It is also known as Griffith's 
Mixture. 

Pills of Carbonate of Iron. Pi/u/oe Ferri Carbonatis. FeOOg 
-|- K^SO^. — Potassium carbonate is rubbed with powdered 
myrrh and then with sulphate of iron, and when 
the reaction has ceased the mass is made into pills with 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 259 

tragacanth, althaea, glycerin and water: FeSO^ -f Na^SO^ 
= FeCOg + Na^SO^. The reaction sometimes does not 
set in until the pills become softened in the stomach. 

Ferric Hypophosphite. Ferri Hypophosphis. Fq^{R^O^^. — 
Made by double decomposition between calcium hypo- 
phosphite and ferrous sulphate : FeSO^ + Ca(H2POj2 
= Fe(H,POJ, (ferrous hypophosphite) + CaSO,. The 
calcium sulphate precipitates, while the ferrous hypophos- 
phite is held in solution. The application of heat during 
the evaporating of the solution changes the ferrous salt to 
the ferric condition. The ferric salt is a white or grayish 
powder, permanent in the air, odorless, nearly tasteless, and 
only slightly soluble in water. Ferric phosphate should 
be absent; if it is not, the salt is not completely soluble in 
acetic acid. 

Hypophosphite of iron was at one time highly recom- 
mended in the treatment of consumption, but its elBBciency 
was probably overestimated. It is now given as a blood and 
nerve tonic in pill or syrup form. Dose up to 0.66 Gm. 

Solution of Ferric Subsulphate. Liquor Ferri Subsulphatis. 
Fe,0(SO,),. — Solution" of Basic Ferric Sulphate, Mor- 
sel's Solutio:n'. — Sulphate of iron is added to a boiling 
mixture of sulphuric and nitric acids until effervescence 
ceases. The following equation approximately expresses 
the reaction: 12FeS0, + 3H,S0, + 4HNO3 = 3Fe,0(S0J, 
-f 5H2O + 2N2O2. The effervescence is due to the dis- 
engagement of the ^fi^ vapors, which, as soon as they are 
generated, unite with two atoms of oxygen, N^O^ + 0^ 
= ISTjO^, becoming the tetroxide of nitrogen, whose fumes, 
and not those of ^'2^2 ^ ^^^^ ^ reddish color. Enough dis- 
tilled water is added to adjust the percentage of metallic 
iron to 13.6. 



260 PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 

MonseFs solution is a dark, reddish-brown, heavy liquid 
of a specific gravity of 1.55. It is nearly odorless, has a veiy 
astringent taste, and is miscible in all proportions with water 
and alcohol. Ferrous salt, which is sometimes present, is 
detected with test-solution of ferricyanide of potassium, 
with which it gives a deep blue color. This solution when 
diluted is the most valuable preparation for stopping bleed- 
ing or external hemorrhages. It is employed internally in 
doses of from 1 to 5 minims, well diluted. In some medical 
works, and among some physicians, the solution of suhsul- 
phate of iron is known as solution of persulphate of iron. 
Whenever the latter is prescribed the former should be dis- 
pensed, according to the U. S. Pharmacopoeia. 

Solution of Ferric Sulphate. Liquor Ferri Tersulphatis. 
Fe2(SOj3. — SoLUTioi^ OF Normal Ferric Sulphate. — 
The method for making this sokition is identical with that 
for the preparation of the preceding, except that the quan- 
tity of HjSO^ is increased sufficiently to convert all of the 
ferrous sulphate employed into the ferric condition: 
12FeS0,+ 6H,S0,+ 4H]Sr03=:6Fe,(SOj3+ 8H,0+2N,0,. 

In comparing the equation expressing the reaction in 
the preparation of the solution of subsulphate of iron with 
that for the solution of tersulphate of iron, it will be seen 
that in the former 3 molecules of H^SO^ are employed, 
and in the latter 6, or just twice as many. This excess of 
H5SO4 in the latter over the former is just sufficient to 
convert the basic ferric sulphate into the normal ferric 
sulphate: 3Fe,0(S0,), -}- 3H.,S0, = 6Fe,(SOj3 + 3H,0. 
The strength of the solution in ferric sulphate is adjusted 
with distilled water to 28.7 per cent. Solution of tersul- 
phate of iron has nearly the same properties as the solu- 
tion of the subsulphate has, differing only in containing 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 261 

more sulphuric acid and having a lower specific gravity — 
1 .32. The solution of the subsulphate, when two volumes 
of it are slowly mixed with one volume of H^SO^ , deposits 
a white solid mass on standing, while the tersulphate solu- 
tion does not. This solution is used principally in the 
preparation of the third series of the iron preparations. 

Ferric Ammonium Sulphate. Ferri et Ammonii Sulphas. 
Fe2(NHj2(SOJ,.24H,0. — Ammonio Ferric Sulphate, 
Ammokia Ferric Alum, Iron Alum. — Made simply by dis- 
solving crystals of ammonium sulphate in solution tersul- 
phate of iron and allowing the double salt to crystallize. 
The salt is in form of pale, violet, eight-sided crystals, ef- 
florescent on exposure to air, sometimes melting in warm 
weather in its water of crystallization. It is odorless, 
styptic and soluble in water, insoluble in alcohol. In form 
of saturated or strong solution it is employed as a styptic. 
It is one of the alums. (See Alums.) 

Ferric Valerianate. FerH Valerianas. ^ejfj^^fi^^. — Solu- 
tion of tersulphate of iron is precipitated with a solution 
of sodium valerianate, the precipitated valerianate of iron 
collected, thoroughly washed and dried. 

It is a dark, tile-red, amorphous powder, having a faint 
odor of valerianic acid ; insoluble in water, soluble in alco- 
hol, and decomposed by boiling water, the valerianic acid 
being set free and ferric hydroxide remaining. The salt is 
very little used in pharmacy. 

Ferric Hydrate with Magnesia. Ferri Oxidum Hydratum cum 
Magnesia. Yq^{OH)^ -\- MgSO^. — Calcined magnesia is 
rubbed to a smooth and thin mixture with water and 
added to tersulphate of iron solution and the whole well 
shaken together. The preparation is official because it is 
antidotal to arsenous acid. It should be freshly prepared 



262 PHAEMACEUTICAL AN^D MEDICAL CHEMISTRY. 

when wanted; the magnesia should be kept ready sus- 
pended in water, next to a bottle containing the prescribed 
amount of the diluted iron solution, so that the prepara- 
tion can be made at a moment's notice. When the two 
are mixed, the magnesia beiug in excess, ferric hydroxide 
and magnesium sulphate are produced: Fe2(SOj3 + 3MgO 
+ 3H,0 = Fe,(OH), + MgSO,. The ferric hydroxide be- 
comes in a short time converted into the oxyhydrate, 
re,0,(OH),, by losing water, thus: Fe,(OH), - 2H,0 
= 'Fefi^{0'K)^; a long exposure converts it finally into 
the ferric oxide, Fe^Og, by losing another molecule of 
water : Yefl^iOK)^ — H,0 = Fe^Og. In the proportion in 
which the ferric hydroxide loses water, it becomes worth- 
less as an antidote to arsenic, hence the great importance 
of making the antidote when needed. The ferric hydrox- 
ide becomes deoxidized by the arsenic and becomes the 
insoluble ferrous arsenate and ferrous hydroxide, according 
to this equation: 2Fe2(OH)g -|- ^s^Og (arsenous acid) = 
Fe3(As20 J2 (ferrous arsenate) + Fe(0H)2 (ferrous hydrox- 
ide) + SH^O. The sulphate of magnesium formed aids, 
through its cathartic action, to remove the insoluble arsenate 
of iron, but it is better to employ prompt emetics shortly 
after the administration of the antidote. 

Ferric Hydrate. Ferri Oxidum Hydratum. Yq^{0^)^. — Instead 
of using, as in the preceding, the oxide of magnesium, the 
hydroxide of ammonium is used as the precipitant in this 
preparation. It is, however, better to pour the solution of 
tersulphate of iron into the ammonia-water, which has been 
previously diluted: Fe,(S0j3 + e^^H^OH = Fe,(OH), + 
3(XHJ2S0^. The whole is poured upon a wet muslin 
strainer and thoroughly washed with water. The product 
is the same as in the preceding, but without the presence 



PHAEMACEUTICAL AKD MEDICAL CHEMISTRY. 263 

of any other salt, since the ammonium sulphate is washed 
out. The ferric hydroxide thus prepared is as efficient an 
antidote to arsenic as the above, the latter having the ad- 
vantage, though, of not being over-acid nor over-alkaline, 
the magnesia being very slightly alkaline and always in ex- 
cess. The XJ. S. P. directs that the ingredients for making 
ferric hydroxide should always be kept on hand, ready for 
immediate use. The hydroxide freshly prepared is a 
brownish-red magma gradually turning into the oxide Fe^Og 
upon exposure or upon drying. It is not used medicinally 
otherwise than stated; pharmaceutically it is of importance, 
inasmuch as from it the fourth series of iron preparations 
including the important scale salts are made. 

Troches of Iron. Trochisci Fern. Fe^O,. — These troches are 
made by massing dried hydroxide of iron with sugar, 
vanilla and mucilage of tragacanth, and cutting into con- 
venient forms, so that each troche contains 0.33 Gm. of the 
dried hydroxide of iron. 

Iron-Plaster. Emplastrum Ferri. — The ordinary strengthen- 
ing plaster contains dried hydroxide of iron incorporated 
with olive oil, Burgundy pitch and lead-plaster by means 
of gentle heat. 

Solution of Ferric Acetate. Liquor Ferri Acetatis. YQ^{(j^fi^^. 
— Ferric hydroxide, freshly prepared from solution tersul- 
phate of iron and ammonia-water and thoroughly washed, 
is dissolved in glacial acetic acid and enough water added 
to the solution to make it contain 31 pel* cent, of an 
hydroferric acetate: Fe,(0H)3 + 6HC,H30,=: Fe,(C,H30J, 
+ 6H2O. The solution is a dark reddish-brown clear liquid 
with a pleasant acetous odor and sweetish taste ; specific 
gravity, 1.16. Ferrous salt may be present and may be 
found as usual with test-solution ferricyanide of potas- 



264 PHAKMACEUTICAL AKD MEDICAL CHEMISTRY. 

sium. This preparation is used principally in the prep- 
aration of the official tincture. 

Tincture Acetate of Iron. Tin ctura Fern Acetatis. Fe^{CJIfi^)^ 
+ O^H^OjHgOj. — Made from the solution of acetate of 
iron by diluting with alcohol and adding acetic ether, 
CjH^OjHgOj. This tincture is preferred by some physi- 
cians, especially by the German, to the tincture of chloride 
of iron. It decomposes in time, light and heat causing it 
to deposit a brown precipitate of probably an oxide. It 
should therefore be kept in a cool and dark place. 

Solution of Ferric Nitrate. Liquor Ferri Nitratis. ^^^{1^0^^. 
— Solution of ferric nitrate is obtained by dissolving freshly- 
prepared ferric hydroxide in nitric acid and adding enough 
water to make the solution contain six per cent of normal 
ferric nitrate. Thus prepared, solution of ferric nitrate is 
a transparent, reddish liquid having a strongly styptic taste 
and acid reaction; specific gravity, 1.05. Medicinally the 
preparation U an astringent tonic, and is given in doses 
up to 10 minims, 0.66 cc. 

Scale Salts. 

The class of compounds known as the Scale Salts of Iron 
is a series of iron preparations made by dissolving freshly 
precipitated ferric hydroxide in tartaric or citric acid or in 
their acid salts, and evaporating the solutions at a low heat 
until of a syrupy consistency, then spreading on plates of 
glass or porcelain, and allowing to dry thereon until the 
compounds separate in scales. The secondary products re- 
main and form part of the compounds, which become, 
according to the acid or acid salt used, potass io-citrate of 
iron or potassio-tartrate of iron, or similar ammonium or 
sodium compounds of iron. They are of varying chemical 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 265 

constitution^ and the formulas and equations following are 
probably only approximate, yet they aid to illustrate the 
composition of the compounds. The separate processes of 
the official scale salts are described below. 

Iron and Potassium Tartrate. Ferri et Potassii Tartras, 
— Potassio-Ferric Tartrate. — Probably Fe2Ke(C,H40 J^. 
To some fresh ferric hydroxide a quantity of acid potassium 
tartrate is added, and after solution has been effected by 
means of a water bath, in which the temperature does not 
rise above 140° F. (or 60° C), the whole is filtered and evapo- 
rated to a syrupy consistency, and poured on glass plates to 
dry and scale. The addition of a little ammonia during 
evaporation prevents the formation of a precipitate after 
solution. The reaction may be according to the equation 
Pe,(OH). + 6KHC,H.O. = Fe,K,(C.H.O.). + 6H,0. This 
and the succeeding compound have a chemical similarity 
to Eochelle salt, the double tartrate of sodium and potas- 
sium — KNaO^H^Og. In the former the hydrogen of the 
acid tartrate of potassium has been replaced by ferric iron, 
Fe^, and in the latter by sodium. The normal tartrate of 
iron is only very slightly soluble. 

This compound is in transparent garnet-red scales, odor- 
less, sweetish, soluble in water but not in alcohol, and is 
used as a mild iron tonic in doses up to 1.00 G-m. 

Iron and Ammonium Tartrate. Ferri et Ammonii Tartras. — Am- 
monio-Ferric Tartrate. — Probably Fe2(NHJg(04H40e)„. 
Prepared as the above, substituting acid tartrate of 
ammonium for the potassium salt. It possesses the same 
properties as the preceding salt does, only being sometimes 
of a yellowish-brown color. The acid ammonium salt is 
made as part of the process by adding carbonate of ammo- 



266 PHAEMACEUTICAL AKD MEDICAL CHEMISTRY. 

nium to tartaric acid in molecular proportions: (NHJ^COg 
+ 2H,C,H,0, = 2NH,HC,H,0, + CO, + H,0. 

Solution of Ferric Citrate. Liquor Ferri Cifrat/s. ¥e^{C^'Kfl^)^. 
— Ferric hydroxide is dissolved in citric acid and the 
solution adjusted to a strength of 35.5 per cent with water. 
Pe,(OH), + 2H,C.HA = Fe,(C.H.O,), + 6H,0. It is 
a dark-brown liquid, odorless, and has a ferruginous taste; 
specific gravity, 1.25. Owing to the fact that it is just half 
the strength of the scales, the pharmacist will find it very 
convenient to use when the citrate is prescribed in aqueous 
solution. 

Soluble Ferric Phosphate. Ferri Phosphas So/ubHis, — Phos- 
phate of sodium is dissolved in a solution of ferric citrate 
and the solution scaled. 1'he scales are a sodio-ferric-citro- 
phosphate. This, like the other scale salts, is not a definite 
compound, and its formula can only be given approximately. 
This scale compound contains Na^HPO^ and re2(C6H50,)2 
in a state of combination. It is in bright-green scales, odor- 
less, very soluble in water and insoluble in alcohol. Its 
advantage over the normal phosphate is in its solubility. 
Dose up to 0.66 Gm. 

Syrup of the Phosphates of Iron, Quinine and Strych- 
nine. Syrupus Ferri, Quininas et Strychninae Phosphatum. — Quinine 
sulphate and strychnine are dissolved in solution of phos- 
phate of iron containing an excess of phosphoric acid, and 
sugar and distilled water added to make a syrup. The ex- 
cess of phosphoric acid dissolves the alkaloids, converting 
them into phosphates. The syrup contains .02 per cent. 
of strychnine alkaloid and 3.00 per cent of quinine 
sulphate. 

Soluble Ferric Pyrophosphate. Ferri Pyrophosphas Solubilis. — 
Ferric Pyrophosphate. Made as the preceding, employ- 



PHARMACEUTICAL AI^D MEDICAL CHEMISTRY. 267 

ing the pyrophosphate in place of the phosphate of sodium. 
It occurs in thin green, transparent scales, and is very freely 
soluble in water, on account of which it is frequently em- 
ployed in solution. Dose up to 5 grains, 0.33 gm. 

Ferric Citrate. Ferri Citras. Fe^{C^'Efi^)^.—The scales of 
citrate of iron are obtained by simply evaporating the solu- 
tion of citrate of iron. They are of a garnet-red color, are 
odorless, and slowly but wholly soluble in water and insolu- 
ble in alcohol. Because the salt is very slowly soluble it is 
not so frequently used as the succeeding one. Dose up to 
1.33 Gm. 

Iron and Ammonium Citrate. Ferri et Ammonii Citras. — Am- 
MOifio-FERRic Citrate. Made, as the above, by the addition 
of a little water of ammonia to the solution of citrate of 
iron before evaporating. The addition of ammonia fur- 
nishes a salt which is more soluble than the above but 
otherwise identical with it. 

Wine of Ferric Citrate, l^inum Ferri Cifratis. — An agreeable 
chalybeate tonic prepared by dissolving citrate of iron and 
ammonium in white wine and adding syrup and tinc- 
ture sweet orange-peel to flavor. It contains 4 per cent of 
citrate of iron and ammonium. Dose, up to 4 cc. Some- 
times called sweet iviiie of iron. 

Bitter Wine of Iron. Vinum Ferri Amarum. — Made by dis- 
solving soluble iron and quinine citrate in white wine and 
adding tincture of sweet orange-peel and syrup. It con- 
tains 5 per cent, of the scale salt. 

Iron and Strychnine Citrate. Ferri et Strychnince Citras. — 
Strychnine is dissolved in a solution of citrate of iron and 
ammonium containing citric acid, and the solution evapo- 
rated and scaled. Thus obtained the. compound is in form 
of transparent garnet-red scales, deliquescent on exposure 



268 PHAEMACBUTICAL AN^D MEDICAL CHEMISTRY. 

to air, odorless, bitter taste, wholly soluble in water and 
only slightly soluble in alcohol. It contains one per cent 
of strychnine. Dose up to 0.20 Gm. 

Soluble Iron and duinine Citrate. Ferri et QuinincB Citras 
Solubilis. — Quinine and citric acid are dissolved in solution of 
citrate of iron, and the whole evaporated and scaled. It 
forms thin, transparent scales of a greenish, golden-yellow 
color. Slowly deliquescent upon exposure to the air, odor- 
less, bitter taste, very soluble in water and but slightly solu- 
ble in alcohol. It should contain 12 per cent, of quinine, 
but very often it is found in the market with a deficiency 
of quinine. 

The Manganese Salts. 

The salts of manganese are not of much importance in 
pharmacy and medicine; there are only two official, the 
dioxide and the sulphate. Manganese is found in nature 
mainly as the dioxide, MnOj , called pyrolusite or braun- 
stein ; the Mn^Og and MngO^ and the carbonate also occur 
in nature. 

Manganese is present in the radical of potassium per- 
manganate. 

Manganese Dioxide. Mangani Dioxidum. MnO,. — Black 
Oxide of Manganese. — The U. S. Pharmacopoeia recognizes 
the native crude product, which contains at least QQ per 
cent of the pure dioxide. It is a heavy, grayish-black 
gritty powder, odorless, tasteless, and permanent in the 
air, insoluble. Its chief use is in the preparation of 
oxygen; when heated it gives off oxygen, becoming the 
Mn30, - 3MnO, + heat = Mn30, + 0,. 

Manganese Sulphate. Mangani Sulphas. MnSO^ + ^^fl. — 
When the dioxide is digested with concentrated sulphuric 



PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 269 

acid the sulphate is formed with the liberation of oxygen : 
2MnO, + 2H,S0, = 2MnS0, + 2H,0 + 0,. This salt 
occurs in colorless or pale rose-colored transparent prisms 
which are somewhat efflorescent in dry air, very soluble 
and of a bitter and astringent taste. 

The aqueous solution of the salt yields with ammonium- 
sulphide test-solution a flesh-colored precipitate, soluble in 
dilute acids. 

If a little of the dry salt is mixed with a little sodium 
hydroxide and the mixture fused, it will yield a dark green 
mass which dissolves in water with a green color. 

The Arsenic Salts. 

Occurrence. — The element arsenic is sometimes found in 
a native state, but the largest proportion is derived from 
the sulphides, realgar, As^S^, and orpiment, As^Sg, and 
from the arsenical iron ores, the latter consisting chiefly of 
FeASg, NiASj and CoAs^. Mispickel, Fc^S^As, is also a 
source, and arsenous acid, As^Og , is found in nature as the 
mineral arsenolite. There are many other forms of occur- 
rence, but they are not utilized much as sources of the 
element. 

Preparation. — The ores, preferably the arsenical iron 
ores, are roasted in a reverberatory furnace and the volatile 
product, crude arsenous oxide, As^Og , condensed in long 
and nearly horizontal chimneys, or in a series of chambers 
made of brick. The arsenic volatilizes and unites with 
oxygen, becoming the arsenous oxide, As^ + 30, = 2AS2O3 , 
which condenses and forms the crude oxide which is puri- 
fied by resublimation. The purified As^Og is then heated 
in retorts with charcoal, which unites with the oxygen. 



270 PHARMACEUTICAL AN^D MEDICAL CHEMISTRY. 

leaving the arsenic in the elementary state as a sublimate : 
2As,03 + 3C, = As, + 600 (or 3C0J. 

Properties, Physical and Chemical. — Arsenic is a steel- 
gray, crystalline solid, having a lustre, and a specific gravity 
ranging from 5.70 to 5.95. It is brittle, tarnishes in air 
but not in pure water, for which reason it is often kept in 
distilled water. When heated it volatilizes, but heated in 
air it becomes oxidized and sublimes as As^Og. It is both 
triad and pentad, more often the former ; its atomic weight 
is 75 (exactly 74.9) and its vapor density (compared to 
hydrogen) 149.8, which is twice its atomic weight, so that 
its molecule in the gaseous state occupies only half as 
much space as the molecule of hydrogen does. Arsenic is 
therefore, like phosphorus, an exception to the rule that 
the atomic weights of elements under similar conditions 
give equal volumes of vapor, or, in other words, that the 
vapor density of an element is half its molecular weight, a 
molecule being supposed to consist of two atoms. 

It appears from this that the molecule of arsenic consists 
of four atoms. As,. Arsenic also, like iron, mercury and 
some of the other metals, forms two series of compounds 
the ShYsenous and the arsenic, exemplified in the oxides 
ASjOg , arsenous, and As^O^ , arsenic. In the former it has 
3 bonds, in the latter 5 : 



a4 



As,0, = >0 

As^ 

\0 



As,0, - / 

As=0 

^0 



Arsenic is considered by some chemists as being a non- 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 271 

metal, but the majority class it as a metalloid {oid means 
like) because its chemical behavior is similar to that of 
the metals in many respects. It behaves in the dual 
capacity, chemically, of a non-metal and of a metal. In 
the former it resembles phosphorus, uniting, e.g., with 
oxygen to form oxides, which oxides with water produce 
the corresponding acids, from which corresponding salts 
may be prepared. The following will illustrate : 



Oxides 


As,03 
+ 3H2O 


ArsenoMS Oxide. 
Water. 


AS2O5 
+ 3H2O 


Arsenic Oxide. 


Acids 


2H3ASO5 
3H2 + 3Ks 

2K3ASO: 


Arsenotts Acid. 
Replacing H by K. 

Arsenate of Potassium. 


2H3ASO4 
-3H2 + 3K2 


Arsenic Acid. 
Replacing H by K. 


Salts 


2K3ASO4 


Arsenafe of Potass 


Oxides 


P2O3 
+ 3H2O 


PhosphoroMS Oxide. 


P2O5 
+ 3H2O 


Phosphoric Oxide. 



Acids 2H3PO3 Phosphorows Acid. 2H3PO4 Phosphoric Acid. 

- 3H2 + 3K2 Replacing H by K. -SHa + 3K2 Replacing H by K. 

Salts 2K3PO3 Phosphide of Potassium, 2K3PO4 Phosphate of Potassium. 

The above are all normal or ortho-compounds. A further 
similarity between phosphorus and arsenic will be seen in 
the following comparison of their meta- and pyro-com- 
pounds : 

Oxides AS2O3 ASjOg 

+ HaO_ +H.,0 

Acids 2HASO2 Metarsenous Acid. 2HASO3 Metaarsenic Acid. 

— H2 -r K2 — Hg -|- K2 

Salts 2KASO2 Metarsenite of Potas- KAsOs Metarsenate of Potas- 

sium, (Fowler's Solution.) sium. 

Oxides P2O3 P2O5 

+ H2O +H2O 



Acids 2HPO2 Metaphosphorous Acid. 2HPO3 Metaphosphoric Acid. 
— H2 -\- K2 — H2 -j- K2 

Salts 2KPO2 Metaphosphite of Potas- KPO3 Metaphosphate of Potas- 

sium, sium. 



272 PHABMACEUTICAL AKD MEDICAL CHEMISTEY. 

In a like manner the pyroacids and pyrosalts may be 
obtained by adding two molecules of water to each of 
the oxides of arsenic and phosphorus. Any other metal 
may be employed to replace the potassium, if in equivalent 
proportions. 

As^Og As^O, 

+ 2H,0 +2H,0 

H^ASjOj, Pyroarsenous acid. H^As^O^, Pyroarsenic acid. 

The salts ortho-, pyro-, and meta-arsenites and arsenates 
are therefore obtained, in theory, by replacing the hydro- 
gen in the acids as above shown — the arsenic in them 
behaves as a non-metal, resembling phosphorus. In the 
other capacity arsenic acts as a metal; that is, it occupies 
the base in a number of salts, in such as AsClg, AsBrg, 
As^Sg, etc. (See Antimony.) 

Important Analytical Reactions. — 1. Hydrogen Sul- 
phide produces in acid solutions precipitate of the yellow 
sulphide, As.Og + 3H,0 + 3H,S = As.Sg + 6 H,0. 

2. Arsenic Salts are soluble in ammonium sulphide: 
As,S3 -f 3(]SrHJ,S - 2(NHj3As,S3. 

3. Marsh's Test consists in reducing arsenic com- 
pounds to metallic arsenic by means of nascent hydrogen. 
With the latter arsenic enters into combination to form 
arsenous hydride or arsenuretted hydrogen, which is iden- 
tified by numerous reactions, but usually by its behavior 
when passed into silver nitrate solution, or when ignited and 
its flame directed upon cold porcelain. The hydrogen is 
usually generated from H^SO^ by means of zinc: 2H2SO4 -|- 
Zn2= 2ZnS0^+ 2^^. The H in contact with arseuic becomes 
ASH3 thus : As.Og -f 6H, = 2H3AS + 3H,0. The HgAs 
is a very poisonous gas, and care should be had not to inhale 



PHARMACEUTICAL AI^D MEDICAL CHEMISTRY. 273 

it. It burns with a yellow flame, producing As^Og thus: 
2H3AS + 30, = 3H,0 + As fi^. If the flame be directed 
against cold porcelain or glass, the reduction of temperature 
prevents the oxidation of the arsenic, and it deposits in black 
or steel-gray spots: 4H3AS -f- 30^ = QB.fi + As^. Anti- 
monure'tted hydrogen produces similar spots under simi- 
lar conditions. (See Antimony), 

The arsenic spots are dissolved by a solution of hypo- 
chlorite of sodium: As, + lONaOlO + 6B.fi = 4H3ASO, + 
lONaCl. (Difference from antimony spots, which remain 
unaffected.) 

If the HjAs is passed into solution of silver nitrate, the 
silver is reduced to metallic condition and precipitates: 
H3AS + 6AgN03 + 3H,0 = 3Ag, + H3ASO3 + 6HNO3. 
This test is usually employed to distinguish arsenic from 
antimony — the antimony precipitates, the arsenic does not. 

4. Fleitman^s Test consists in generating hydrogen 
from metallic zinc or aluminum and strong solution of soda 
or potassa by heating. The addition of the solution of an 
arsenic salt will produce arsenuretted hydrogen, which 
may be tested as above: 2k\ + 4K0H + As.Og + H,0 = 
2H3AS + 2K,A1,04. The value of this method is that it 
does not produce antimonuretted hydrogen, affording a 
ready means of distinguishing between arsenic and anti- 
mony salts. 

5. Reinsch's Test is applied by adding a piece of bright 
copper to an (HOI) acidulated solution of an arsenic salt 
and boiling. If arsenic is present, the copper will become 
coated with a deposition of metallic arsenic. It is essential 
that the copper be chemically pure. 

6. Berzelius' Test. When the arsenic oxides are heated 
in a long test-tube with charcoal, the arsenic becomes re- 



274 PHARMACEUTICAL AKD MEDICAL CHEMISTEY. 

duced to the metallic condition and deposits on the inside 
of the tube as an iron-gray mirror. Arsenic in state of 
vapor has a garlicky odor, which may be noticed in the 
carrying out of this test. The vapor is poisonous. 4AS2O3 
+ 30, = 2As,+ 600,. 

7. Ammoniacal Solutions' of Oopper Sulphate gives a 
grass-green precipitate in solutions of arsenic. The preci- 
pitate dissolves in XH^OH. It consists of OUgASgOg-SH^O 
(or 3OuO.AS2O3.2H2O) and is known as Scheele's green. 

8. Ammonio-Nitrate of Silver Solution produces a 
lemon-yellow precipitate of arsenite of silver in solutions 
of arsenic, which dissolves in an excess of ammonia. (Am- 
monio-nitrate of silver solution is prepared by adding 
NH^OH to AgNOg until the precipitate at first produced is 
nearly all dissolved.) 6NH,0H + BAgNOg + 2As,03 = 
2Ag3As03 + 6NH,N03 + 3H,0. 

Arsenous Oxide. Acidum Arsenosum. As^Og. — White Arse- 
nic. — This compound is popularly known as arsenic and 
as arsenous acid. Both terms are incorrect, but they have 
been so thoroughly established by usage that the Pharmaco- 
poeia has not -discarded their use. 

Arsenous acid consists, as shown above, of H3ASO3; all 
acids contain hydrogen. The As^Oa is obtained, as above 
shown, in the preparation of metallic arsenic. From it all 
other pharmacopoeial compounds are made. It is a heavy, 
white, opaque powder or semi-transparent mass, perma- 
nent in the air, volatile when heated, odorless, tasteless, 
slowly soluble in water, freely in HCl and in the alkaline 
hydroxides and carbonates. Its strength of purity should 
be at least 98.80 per cent. 

Arsenous acid is very poisonous and is often bought with 
suicidal intention; the careful pharmacist will only dispense 



PHARMACEUTICAL AND MEDICAL CHEMISTEY. 275 

it upon physicians^ orders. Its antidote, as for all arsenic 
compounds, is freshly precipitated ferric hydroxide (see 
Ferric Hydroxide), which forms an insoluble, and hence 
harmless, salt with it: 2Fe,(0H), + As,03 = Fe3(AsOJ, 
(ferrous arsenate) + Fe(0H)5 (ferrous hydroxide) + SH^O. 

The oxide is given in doses up to 0.003 Gm. Medici- 
nally it is an alterative. 

Solution of Arsenous Acid. Liquor Acidi Arsenosi. H3ASO3. 
— This preparation is a solution of the oxide As^Og in 
water, the solution being aided by heat and the addition of 
a small quantity of hydrochloric acid. The latter does not 
enter into combination with the oxide; it merely facilitates 
solution. 

The solution is a convenient means for the administra- 
tion of arsenic in liquid form, but it is less popular with 
physicians than the following. Dose is up to 5 minims, 
0.33 cc. It contains 1 per cent of As^Og. 

Solution of Potassium Arsenite. Liquor PotassH Arsenitis. 
KAsOj. — This solution, popularly known as Fowler's Soke- 
Hon, is prepared by boiling together arsenous acid and 
potassium bicarbonate until solution ensues, flavoring with 
compound tincture of lavender, and filtering after a 
week: As,03 + 2KHOO3 = 2KAsO, + 2C0, + H,0. 

Chemists are not certain whether the two salts react 
upon each other, and if they do, whether the orthoarsenite, 
K3ASO3 (or KH^AsOg), or the metarsenite, KAsO^, is 
formed. It is probable, though, that the latter is formed. 
The solution contains 1 per cent. As^Og. It is an agreeable 
preparation and is used more extensively than any other 
form of arsenic. Dose is up to 5 minims, diluted. It 
should never be kept longer than a year, as after that time 
and often before, it begins to deposit the arsenous oxide. 



276 PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 

becoming proportionately weaker, and creating the possi- 
bility of poisoning by the careless administration of the 
deposit. The solution should never be dispensed unless 
it is perfectly clear and transparent. 

Arsenic Iodide. Arseni lodidum. Aslg. — The iodide is made 
by directly combining iodine with arsenic, the union being 
facilitated by dissolving the iodine in disulphide of cai-bon 
and adding the arsenic in powder until the purple color of 
the iodine disappears, carefully evaporating and crystalliz- 
ing: As^ -|- 6I2 = 4ASI3. The arsenic iodide thus pre- 
pared is in shining, orange-red crystalline scales losing 
iodine upon exposure to air; volatile, soluble in water and 
alcohol, gradually decomposing in solution. This com- 
pound is rarely used by itself, but is usually combined with 
iodide of mercury in the preparation of Donovan's Solution. 

Solution of Arsenic and Mercuric Iodide. Liquor Arseni ef 
Hydrargyri lodidi. AsIg.Hglg. — One per cent of each of the 
iodides of arsenic (arsenic) and mercury (mercuric) are 
dissolved in water and the solution filtered. Probably 
no chemical reaction takes place. The solution should be 
of a light straw-color; any deeper color is due to the pres- 
ence of disengaged iodine, and may be removed by the 
addition of a globule of mercury, or of a few grains of 
metallic arsenic, and filtering. This solution, like the other 
arsenic and mercury preparations, is an alterative. Dose, 
up to 5 minims, diluted. 

Sodium Arsenate. Sodii Arsenas. ]Sra2HAsO,.7H20.— See 
Sodium Salts. 

Solution of Sodium Arsenate. Liquor Sodii Arsenatis.—A 
preparation containing one per cent of sodium arsenate 
dissolved in distilled water. 

Paris Green. — This unofficial arsenic compound is an 



PHAEMACEUTICAL AND MEDICAL CHEMISTRY. 277 

ciceto-arsenite of copper prepared by boiling solution of 
arsenous acid with solution of acetate of copper. It is of 
variable composition and may be any of the following: 

3(CuO.As,03).Cu(0,H30,),; 
3(CuO.As,03).2Cu(C,H30J,; 
5(CuO.As,03).2Cu(0,H30,), + 2H,0; 
5(CuO.As;03).20u(0,H30J, + 5H,0. 

The last is considered to be the best. It is often termed 
Vienna or Imperial Green. It should be sold with caution, 
being exceedingly poisonous. 

Antimony Salts. 

Occurrence. — Antimony occurs with arsenic chiefly as a 
sulphide, SbgSg, and also native. The former when freed 
from earthy impurities by fusion constitutes the crude or 
hlack antimony of the market. 

Preparation. — The metal may be obtained from its 
ores by heating them with carbonates of potassium or so- 
dium, or with metallic iron, which retains the sulphur, or 
by roasting and heating with charcoal. The latter is the 
method usually employed. 2Sb2S3 -|- heat -}- QO^ = 2Sb,03 
+ 6S0„ 2Sb,03 + 20, = 2Sb, + 200, + 200 (00, + 00 
in variable proportions). 

The metal is not used in pharmacy; the purified sul- 
phide furnishes directly or indirectly all of the preparations 
of the Pharmacopoeia. Metallic antimony has numerous ap- 
plications in the arts; type-metal, pewter, etc., are alloys 
containing it. 

Properties. — Antimony is a bluish-white metal, lustrous, 
very brittle, and hence easily pulverized; specific gravity, 
6.8; volatile at high heat. 



278 PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 

It does not oxidize in the air at ordinary temperatures, 
but when strongly heated it burns, producing the oxide 
SbjOg. Dissolved in nitric acid it is oxidized to antimonic 
acid ; hydrochloric acid dissolves it, forming a chloride, 
SbClg, and free hydrogen. Antimony has chemical proper- 
ties very similar to those of arsenic ; it forms two classes of 
compounds — the antimonous and antimonic. In the 
former it is trivalent, SbClg, Sb^Sg, Sb^Og, in the latter 
quinquivalent, Sb^O^, SbCl^, Sb^S^. 

Graphically, antimonous compounds may be thus ex- 
pressed : 

SbCl3: S\0,: 

/CI ^h^O 

\oi Vo 

Antimonic thus, 

SbCl,: Sb^O,: 

/Cl ^0 

y>Cl Sb=0 

Sb^— CI >0 

\>C1 Sb=0 

\C1 ^0 

The atomic weight of antimony is 120; its molecule con- 
sists of two atoms, Sb^. Nearly all that has been said of 
the chemical behavior of arsenic is also true of antimony. 
Antimony forms the base in some compounds, SbClg, and 
the radical in others, NaSbO^ sodium antimonite. 

The trioxide Sb^Og unites with watfer to form antimon- 
ons acid, Sb,03 + H,0 = 2HSbO, , which forms salts 
called antimonzYes by having its hydrogen replaced by a 
metal, e.g. KSb^O, antimonite of potassium. 



PHARMACEUTICAL A^D MEDICAL CHEMISTRY. 279 

The pentoxide produces the antimouic acid with water, 
SbjOg + HjO = 2HSb03 , from which antimona^e^ are ob- 
tained. Both tliese acids are monobasic. The Sb^O^ yields 
also a dibasic acid with H^O, thus: Sb^O^ + 2B.^0i = 
H.Sb,0,. 

Important Reactions (see also Arsenic). — 1. H^Sin acidi- 
fied solutions of antimony salts gives orange-red precipitate. 

2. Ai^TiMON"Y Salts dissolve in (NHJ^jS^: 2Sb2S3 
+ 6(NHJ,S, = 4(NHj3SbS, + S,. 

3. Marshes Test, employed as for arsenic, yields anti- 
monuretted hydrogen, H3Sb: Sb,03 + 6H, == 2H3Sb 
+ SH^O. The HgSb ignited and its flame directed upon 
cold porcelain produces black spots by the deposition of 
metallic antimony. These spots remain unaffected with solu- 
tions of hypochlorites (arsenic spots dissolve and disappear). 

If HgSb is passed into silver nitrate solution, the anti- 
mony is precipitated (Arsenic remains in solution) : HgSb 
+ 3AgN03 = Ag3Sb + 3HNO3. 

4. Aktimoi^y is precipitated from its solution as black 
powder by iron or zinc; copper removes it from solution 
in form of metallic film. 

5. A CON'CEKTRATED SOLUTIOlSr OF THE OhLORIDE 

poured into water produces a precipitate of the oxychlo- 
ride: SbCl3 + H,0 = SbOCl + 2HC1. 

Antimony Sulphide. Antimonii Sulphidum. Sb^Sg. — The crude 
ores are fused in such a way that most of the earthy im- 
purities are removed. When cold the sulphide is in steel- 
gray masses of metallic lustre, or in black lustreless pow- 
der, odorless, insoluble, tasteless. The TJ. S. P. directs it 
to be "as free from arsenic as possible." It is used mainly 
to prepare the purified sulphide in pharmacy, and as an 
alterative in veterinary practice. 



280 . PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Purified Antimony Sulpliide. Antjmonii Sulphidum Purifhatum. 

SbjSg. — The above-described sulphide, finely powdered, 
is macerated for several days witli ammonia- water, thor- 
oughly washed and dried. The ammonia-water dissolves 
the sulphide of arsenic, which is associated with the anti- 
mony in the ores, leaving the antimony sulphide as residue 
(see Second Eeaction of Arsenic Salts). 

The sulphide thus purified is a dark-gray powder, odor- 
less, tasteless, insoluble in water, soluble in hot hydro- 
chloric acid with the evolution of H^S gas. It should not 
contain more than mere traces of arsenic. The orange-red 
precipitate obtained by passing H^S gas into solutions of 
antimony has the same composition, Sb^Sg. It is changed 
to the black variety by heating. 

It is not used internally, but enters into the preparation 
of the Sulphurated Antimony. 

Sulphurated Antimony. Antimonium Sulphuratum. Sb^Sg.- 
Sb^Og. — This preparation, sometimes called Kermes Min- 
eral, is obtained by boiling the purified antimony sulphide 
with soda solution and adding sulphuric acid : GNaOH 
+ Sb^Sg = NagSbOg (sodium antimonite) + NagSbSg (so- 
dium sulph-antimonite) -{- SH^O. To the hot solution of 
the latter two compounds H^SO^ is added which precipi- 
tates the sulphide and oxide : 2]^a3Sb03 + SlSTagSbSg 
+ 6H,S0, = 6Na,S0, + Sb.Sg + ^\0, + 3H,S + 3H,0. 
The precipitate, consisting almost wholly of the Sb^Sj , 
is thoroughly washed to remove the sodium sulphate 
which remained in solution and dried. It is a reddish- 
brown amorphous powder, odorless, tasteless, insoluble. 
It should be free from sulphate, ascertained with Bad,. 
(There are many varieties of sulphurated antimony ; the 
above is the official one.) 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 281 

It is emetic and alterative in doses up to 0.330 Gm. 
Usually given in pill form. 

Compound Pills of Antimony. PHulae Antimonii Compositae, 
Plummer's Pills. — Pills containing each 0.040 Gm. of sul- 
phurated antimony, 0.040 Gm. of calomel and 0.080 Gm. of 
guaiac made into mass with mucilage of tragacanth. No 
chemical reaction takes place between the ingredients. 
Given in skin diseases. 

Antimony Oxide. Antimonii Oxidum. Sb^Og. — Obtained by 
dissolving ^^^^^ in hydrochloric acid, pouring the solution 
into much water and treating the resulting precipitate with 
ammonia-water : Sb^Sg -f 6HC1 — 2SbCl3 (antimonous 
chloride) + 3H,S. 10SbOl3 + 15H,0 = 5Sb,03 (antimon- 
ous oxide) + 30 HCl. Not all of the SbOlg is converted 
into the oxide, but some becomes the oxychloride, SbClO : 
2SbOl3 + 2H,0 = 2Sb010 + 4HC1. The SbClO is con- 
verted into the oxide by having its chlorine removed with 
NH^H : 2SbC10 + 2NH3 + H.^0 = ^\0, + 2NH,C1. 
Oxide of antimony is a whitish powder, permanent in the 
air, odorless, tasteless, almost insoluble in water, insoluble 
in alcohol, soluble in hydrochloric or nitric or tartaric acids. 
It should be free from arsenic, chloride and sulphate. It 
enters into the preparation of antimonial powder and 
tartar emetic. 

Antimonial Powder. Pulvis Antimonia/is. Sb^Og + 0a3(P0j2. 
— A powder consisting of 33 per cent oxide of antimony 
and 67 per cent precipitated phosphate of calcium, and 
given as a diaphoretic in doses of 0.20 to 0.330 Gm. 

Antimony and Potassium Tartrate. Antimonii et Potassii 
Tartras, 2KSbOC,H,0,.H,0, Tartar Emetic— Made by 
boiling together antimony oxide and potassium bitartrate 
and allowing the solution to crystallize : 2^.110 Jlfl^ -\- 



282 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

Shfl, = 2KSbOC,H,0, + H,0. The hydrogen in the base 
of the acid tartrate of potassium is replaced by SbO. 
Tartar emetic is in form of granular powder or as small 
transparent crystals, of a sweetish taste, soluble in water, in- 
soluble in alcohol. It should be free from arsenic. 

This is the most important of the antimony compounds, 
being used extensiyely, as its name indicates, as an emetic. 
All the antimonial preparations have more or less emetic 
properties, a fact which accounts for the absence of cases of 
poisoning by antimony. The antidote would be tannin, 
w^hich produces the insoluble tanuate of antimony. 

Wine of Antimony. I^inum Antimonii. KSbOO^H^Oe. — A 
preparation made by dissolving 4 parts of tartar emetic in 
1000 parts white wiue containing 150 parts of alcohol. It 
is usually added to expectorant mixtures. Dose, 5 to 10 
minims. 

Bismuth Salts. 

Occurrence. — Bismuth occurs in the metallic state, and 
often as sulphide associated with traces or more of arsenic. 

Properties. — Bismuth is a grayish-white metal with a 
pinkish tint; it is crystalline, brittle, brilliant; specific 
gravity 9.8, and has some resemblance to metallic anti- 
mony. Chemically it is closely allied to antimony. It is 
usually trivalent, sometimes quinquivalent; atomic weight 
208.9. There are only four of its compounds ofl&cial, and 
beyond the employment in medicine it is little used. 

Analytical Reactions. — 1. Water precipitates from acidu- 
lated bismuth solution white basic salts which contain 
more or less of the acid radical in proportion as little or 
much water is used: BiClg + H,0 = BiOCl + 2HC1 (see 
Antimony). 



PHARMACEUTICAL AKD MEDICAL CHEMISTRY. 283 

2. Alkaline Hydroxides precipitate bismuth hy- 
droxide: BiClg + 3K0H = Bi(0H)3 + 3KC1. 

3. Hydrosulphuric Acid aj^td Sulphides produce 
black precipitate of Bi^Sg which is insoluble in alkali sul- 
phides, affording a means of separating bismuth from ar- 
senic and antimony: 2BiCl3 + 3H,S = Bi.Sg + 6HC1. 

Bismuth Subnitrate. Bismuthi Subnitras. BiONOg.H^O. — 
Prepared in a necessarily circumstantial way by dissolving 
bismuth in diluted nitric acid, diluting the resulting solu- 
tion with a prescribed quantity of water, and allowing to 
stand for a day, then filtering. The filtered solution is 
then poured into a solution of sodium carbonate during 
constant stirring, the precipitate drained and washed and 
dissolved in nitric acid. The nitric-acid solution is again 
allowed to stand for a day, then again diluted with a pre- 
scribed quantity of water, and some water of ammonia 
added, and the precipitate thoroughly washed and dried. 

Metallic bismuth as a rule contains arsenic, and in the 
above process provision is made for its separation. The 
rationale of the process is as follows : The bismuth dis- 
solves to bismuth nitrate in nitric acid, and some of the 
arsenic becomes arsenic acid: Bi^ + 8HNO3 = 2Bi(N03)3 
bismuth nitrate (normal), + N,0,+4H,0, 3As,+20HNO3 
+ 8H,0 = I2H3ASO,, arsenic acid, + lON^O,. 

The bismuth nitrate and the arsenic acid react upon each 
other, producing bismuth arsenate, Bi(N03)3 + H3ASO4 = 
BiAsO^ + 3HNO3. Both of these salts when their solu- 
tion is diluted with water begin to separate and deposit, 
but the arsenate needs less water to cause it to separate 
than the nitrate does, and hence just enough water is added 
to the solution to cause the arsenate, but not the nitrate, to 
deposit. "When the arsenate has deposited, after a day^s 



284 PHARMACEUTICAL A^D MEDICAL CHEMISTRY. 

standing, it is removed by filtration. Any arsenate which 
may not have deposited when the sodium carbonate is 
added becomes the very soluble arsenate of sodium, which 
remains in solution while the bismuth is precipitated as the 
insoluble subcarbonate : Na^COg + HgAsO^ = Na^HAsO^, 
arsenate of sodium, + H,0 + CO,. SNa.COg + 261(^03)3 
= Bi,0,003, subcarbonate bismuth, -f GNaNOg + 2C0,. 
The subcarbonate is washed and the arsenate of sodium 
removed in the washings. As a further precaution to in- 
sure the entire absence of arsenic, the subcarbonate is again 
dissolved in nitric acid, and the solution again diluted to a 
point at which any arsenic still present will precipitate 
according to above equation. 

After some time the normal nitrate is converted into the 
subnitrate or oxynitrate by further dilution with water and 
the neutralization of the nitric acid present with ammonia 
water: Bi(N03)3 + H,0 = BiON03 + 2HNO3, HNO3 + 
NH.OH = NH,N03 + H,0. The subnitrate of bismuth 
thus prepared is a heavy white powder permanent in the 
air, odorless, almost tasteless and insoluble. It should be 
free from carbonate : effervescence with acids would indi- 
cate its presence. 

Subnitrate of bismuth is largely used in stomach troubles 
as sedative and tonic. Dose up to 0.66 Gm. 

Bismuth Subcarbonate. Bismuth/' Subcarbonas. Bi202C03.- 
H2O. — The subcarbonate is made as above shown in the 
making of the subnitrate. (See the preceding for equa- 
tions and rationale.) 

It is a pale yellowish-white powder, permanent in the 
air, odorless, tasteless and insoluble. It may contain more 
impurities than the subnitrate because in the latter the 
process of purification is further carried on, especially in 



PHARMACEUTICAL AND MEDICAL CHEMISTRY. 285 

the elimination of arsenic. The impurities which may be 
present are insoluble foreign salts, alkalies and alkaline 
earths, lead, copper, chloride and sulphate, and traces of 
arsenic and antimony. 

Its use is similar to that of the subnitrate, and the dose 
the same. 

Bismuth Citrate. Bismuth! Citras. BiCgH^O,. — This salt is 
prepared by boiling bismuth subnitrate with citric acid and 
water for 15 or 20 minutes, or until a drop of the mixture 
dissolves in ammonia-water. Then the suspended matter 
is allowed to subside, the solution decanted and the 
deposit washed with water on a filter until the washings 
are tasteless. Thus obtained it is usually an amorphous 
powder without taste or odor and insoluble in water, but 
soluble in ammonia-water and in solutions of the citrates 
of the alkalies. It is official mainly for its employment in 
the bismuth and ammonium citrate. Incomplete wash- 
ing in its preparation usually results in the presence of 
nitrate in the salt. The usual test for nitrates should be 
applied. 

Bismuth and Ammonium Citrate. Bismuth! et Ammoni! Citras. 
— The introduction of this salt into medicine was mainly 
to obtain a soluble salt of bismuth. It is not a definite 
compound, but it is soluble. Its preparation consists in 
dissolving bismuth citrate in ammonia-water, evaporating 
(which also dispels all excess of ammonia) to a syrupy con- 
sistency, and spreading on plates of glass or porcelain, so 
that when dry the salt may be obtained in scales. The 
product should be kept in small well-stoppered bottles 
protected from light. The small shining, pearly scales are 
odorless and have a slightly metallic taste. They become 



386 PHARMACEUTICAL AND MEDICAL CHEMISTRY. 

opaque and less soluble if exposed to the air, hence the 
Qecessity of keeping them in well-closed vessels. 

The presence of ammonia in the compound can easily be 
detected by boiling with soda or potassa solution, which 
liberates the ammonia, which may be detected by its 
odor. 



INDEX 



A 

Acetate of ammonium, solution, 
204 

— of iron and ammonium, solu- 
tion, 355 

— of lead, 228 

potassium, 181, 196 

sodium, 196 

zinc, 222 

Acetic ether, 265 
Acetylene, 59. 60 
Acid, acetic, 58 

— arsenic, 156 

— arsenous, 156 

— benzoic, 196 

— boric, 107, 108, 109, 110, 113, 
197 

— bottle, 124 

— chamber, 128 

— chlorazotic, 144 

— chloronitric, 144 

— chromic, 158 

— generator, 123 

— hydj-iodic, 91, 148 

— hydrobromic, 91 
dilute, 145 

— hydrobromic, Fothergill's, 146 

— hydrochloric, 93, 139, 140 
dilute, 144 

— hydrocyanic, 65, 143, 247 

— hydrofluoric, 86, 91 

— hydrosulphuric, 91 

— hyponitrous, 50 

— hypophosphorous, 151 

— iodic, 83 

— iodous, 83 

— metaphosphoric, 151 

— nitric, 50, 134 
dilute. 139 



Acid, nitrohydrochloric, 144 
dilute, 145 

— nitromuriatic, 144 

— nitrous, 50 

— oleic, 241 

— orthoboiic, 111 

— orthophosphoric, 151 

— oxalic, 217 

— oxides, 115 

— pan, 128 

— periodic, 83 

— phosphoric, 93, 102, 149 

anhydrous, 151 

glacial, 151 

ortho, 151 

varieties of, 151 

— phosphorous, 149, 151 
varieties of, 153 

— pyroboric, 112 

— pyrophosphoric, 112, 151 

— prussic, 65 

— sulphuric, 93, 125 

aromatic, 131 

dilute, 131 

— tartaric, 96 

— valerianic, 204, 322 

— valeric, 204 
Acids, 72 

— chemically pure, 123 

— dibasic, 130 

— inorganic, 115 [125 

— medicinal properties of the, 

— medicinally pure, 122 

— monobasic, 120 

— tribasic, 120 

— antidotes to, 135 
Acidulous radical, 95, 118 
Air, 51 

— chemical constituents of, 53, 54 

387 



288 



IKDEX. 



Air, composition of air going into 
the lungs, 54 

— composition of air coming out 
of the kings, 54 

— pressure of the, 52 

— pump, 52 

— weight of, 52 
Alchemy, 22 

Aflfinity, simple elective, 77 
Alkali, fixed, 173 

— volatile, 173 

— hypothetical, 173 
Alkalies, 6, 172 

— properties of the, 173 
Alkaline earths, 6 

— earth metals, 207 

oxides, 115 

Alkaloids, 49, 51, 61, 83 
Allotropic forms of some ele- 
ments, 7, 56, 99, 100 

Alloys, 160, 278 

Aloes and iron pills, 257 

Alum, 225 

— ammonia, 225 

— ammonio-ferric, 176, 262 

— burnt, 225 

— caesium, 176 

— chrome, 176 

— clay, 225 

— dried, 225 

— exsiccated, 225 

— hydrous, 225 

— iron, 176 (iron) 

— potassa, 225 

— potassium, 225 
Alumen, 225 
Alumini hydras, 226 

— sulphas, 226 
Aluminum, 224 

— hydrate, 226 

— hydroxide, 225 

— isolation of, 224 

— properties of, 224 

— salts, 224 

impurities in, 225 

— sulphate, 236 
Alums, 175 
Amalgamation, 234 
Amalgams, 160 
Ammonia, 199 

— albuminoid in well-water, 45 

— aromatic spirit of, 202 



Ammonia aromatic precipitate 
in, 202 

— generation of, in nature, 50 

— in illuminating gas, 60 

— in rain-water, 45 

— in well-water, 45 

— liniment, 202 

— process for sodium bicarbon- 
ate, 191 

— spirit, 202 

— water, 201 

stronger, 201 

Ammoniacal gas-liquor, 200 

— solution copper sulphate, 274 
Ammoniated mercury, 239, 242 

ointment of, 243 

Ammonii Benzoas, 204 

— bromidum, 204 

— carbon as, 203 

— chloridum, 201 

— iodidum, 205 

— nitras, 204 

— valerianas, 204 
Ammonio-ferric alum, 176, 262 
citrate, 268 

sulphate, 262 

tartrate, 266 

magnesium phosphate, 217 

nitrate of silver solution, 275 

— -sulphate of copper solution 
274 

Ammonium, 65, 177, 199 

— acetate, solution of, 204 

— benzoate, 204 

— bicarbonate, 202, 203 

— bromide, 204 

— carbamate, 203 * 

— carbonate, 203 

— chloride, 201 

crude, 201 

granular, 201 

— iodide, 205 

— nitrate, 204 
granular, 204 

— phosphate, 217 

— salts, 199 

impurities in, 201 

— ' — properties of, 199 

sources of, 200 

tests for, 200 

— ' valerianate, 204 
Ammonia valerianate elixir, 205 



INDEX. 



289 



Ammonia valerianate, commer- 
cial, 205 
Amorphous, meaning of, 8, 56 
Amyloses, 61 
Analysis, 8, 35 

— volumetric, 198 
"Analytical reactions aluminum 

salts, 324 

— ammonium salts, 200 

— antimony salts, 278 

— arsenic salts, 273 

barium salts, 216 

bismuth salts, 283 

copper salts, 232 

iron salts, 249 

lead salts, 228 

lithium salts, 206 

magnesium salts, 217 

mercury salts, 235 

potassium salts, 178 

silver salts, 245 

— ' sodium salts, 190 

strontium salts, 214 

zinc salts, 220 

Animal charcoal, 58 
purified, 58, 143 

— kingdom, 55 
Animalculse, 46 
Anhydrides, 116 
Anhydrous salts, 38 
Antacids, 114, 184, 218 

— mild, 198 
Antidotes to acids, 125 

antimony salts, 283 

arsenic salts, 157 

lead salts, 228 

mercury salts, 234 

silver salts, 246 

Antiferment, 194, 197 
Antimonial powder, 282 
Antimouiates, 278 
Antimonii et potassii tartras, 

282 

— oxidum, 281 

— sulphidum, 280 

puriflcatum, 280 

Antimonic compounds, 278 
Antimonites, 278 
Antimonium sulphuratum, 281 
Antimoniuretted hydrogen, 273 
Antimonous compounds, 278 

— oxide, 282 



Antimony, 278 

— and potassium tartrate 282 

— black, 278 

— chloride, 282 

— crude, 278 

— oxide, 281 

— oxychloride, 278, 282 

— pills, compound, 281 

— salts, 278 

antidotes to, 283 

occurrence of, 278 

preparation of, 278 

properties of, 278 

— sulphide, 280 
purified, 280 

— sulphurated, 281 
varieties of, 281 

— tartarated, 282 

— trioxide, 278 

— wine of, 283 
Antiferments, 111 
Antiseptics, 194, 221, 226, 238 ] 

— dressings. 111 
Antispasmodics, 222 
Aputite, 208 
Aqua-ammoniae, 201 
fortior, 201 

— chlori, 68, 78 
Aquafortis, 138 
Aqua-regia, 144 

Arabic words gali and galaj, 

173 
Argeutum, 244 
Argols, 178 

Aromatic spirit of ammonia, 202 
precipitate in, 202 

— waters, 213 
Arsenate of copper, 232 

sodium, 194, 198, 277 

solution, 198, 277 

Arseni iodidum, 276 
Arsenic, 270 

— analytical reactions, 273 

— antidote, 263 

— and mercuric iodide solution, 
277 

— compounds, 271 

similarity to phosphorus 

compounds, 271 

— iodide, 276 

— oxide, 270 

— salts, 157, 270 



290 



IN^DEX. 



Arsenic, salts, occurrence of, 
270 

preparation of, 270 

properties of, 270 

— sulphides, 270 

— test, Berzelius', 274 

Fleitmann's, 274 

Marsh's, 273, 279 

Reinsch's, 274 

— White, 275 
Arsenical iron ores, 270 
Arseuolite, 270 
Arsenous acid, 275 
solution, 276 

— compounds, 270 

— oxide, 156, 270, 275 

antidote to, 157 

preparation of, 157 

properties of, 157 

Arsenurelted hydrogen, 273 
Atmosphere, 51 
Atmospheres, 53 

Atomic force, 3, 8 

— weights of elements, 8, 10 

standard, 12 

Atomicity, 14 

Atoms, 2 

— definition of, 2 

— kinds of, 3 

Avogadro's law (lines 3-10), 10 
Azote, 48 

B 

Balsam tolu for coating pills, 259 
Bandages, borated, 111 
Barii dioxidum, 216 
Barium, 216 

— carbonate, 216 

— chloride, 316 

— dioxide, 216 

— hydroxide, 216 

— nitrate, 216 

— salts, 216 

— sulphocarbolate, 197 
Barometer, 53, 234 
Base for paints, 231 
Bases, 95, 118, 119. 120, 164 

— affinity of chlorine for, 77 
Basham's mixture, 255 
Basic bismuth carbonate, 167 
chloride, 167 

— ferric sulphate, 167 



Basic ferric sulphate, solution of, 
260 

— mercuric sulphate, 243 

— oxides, 115 

— salts, 166, 283 
Basylous radical, 95, 118 
Bearer of light, 99 
Beet-root sugar, 178 
Benzoate of ammonium, 204 
lithium, 206 

sodium, 196 

Benzoic acid, 196 
Berzelius' test for arsenic, 274 
Biborate sodium, 108 
Bicarbonate of ammonium, 203 

calcium, 41 

lead, 229 

potassium, 180 

sodium, 193 

commercial, 193 

purified, 193 

troches, 198 

Binary theory of salts, 165 

Biniodide of mercury, 239 

By-products, 126 

Birth of chemical science, 23 

Bisalts, 95, 120 

Bismuth, 283 

— and ammonium citrate, 286 

— citrate, 285 

— group of metals, 6 

— hydroxide, 283 

— salts, 283 

impurities in, 285 

occurrence of, 283 

properties of, 283 

reactions of, 283 

separation of arsenic in 

— preparation of, 284 

— subcarbonate, 283 
impurities, 285 

— subnitrate, 283 
preparation of, 284 

— sulphide, 283 
Bismuthi citras, 285 

— et ammonii citras, 286 

— subcarbonas, 283 

— subnitras, 283 
Bisulphite of sodium, 194 
Bittern, 85 

Bitter waters, 192 
Bivalent atoms, 14 



IJS^DEX. 



291 



Black antimony, 278 
Bleaching agents, 198 

— powder, 70, 79 
Blowpipe, 109 

— oxyhydrogen, 30 
Blue mass, 336 

— ointment, 236 

— pill, 236 

— stone, 232 

— vitriol, 232 

Bonds, 12, 13, 92, 93, 94, 95 
Boneblack, 56 
Bones, 97 
Boracic acid, 110 
Borated bandages. 111 

— cotton, 111 

— gauzes, 111 

Borate of sodium, 107, 197 
Borax, 107, 111, 112, 113 

— and honey, 114 

— bead, 109 

— lakes, 112 

— springs, 107, 108 

— test for purity of, 113 
Boric acid, 107, 108, 197 

dusting-powder, 111 

ointment, 111 

tests for purity, 110 

uses in pharmacy. 111 

Boron, 107 

— occurrence, 107 
Brandt, chemist, 97, 99 
Brass, 161 

Braunatein, 22, 67, 269 
Brines, 67, 85 
Britannia, 161 

Bromide of ammonium, 204 

— calcium, 85, 209 

— lithium, 206 

— magnesium, 85 

— potassium, 185 

— sodium, 194 

— strontium, 215 
-^ zinc, 221 
Bromides, 162 

— test for, 86 
Bromine, 85 

— compounds of, 86 

— occurrence of, 85 

— preparation of, 85 

— properties of, 86 

— test for, 86 



Bronze, 161 
Brownstone, 22, 67 
Burnt alum, 226 



Caesium alum, 176 
Cailletet, 49 
Calamine, 220, 222 
Calcination, 97 
Calcined magnesia, 218 
Calcite, 208 
Calcii bromidum, 209 

— carbonas prgecipitatum, 209 

— chloridum, 209 

— hypophosphis, 195, 212 

— phosphas prsecipitatus, 213 
Calcium, 207 

— acid phosphate, 196 

— bicarbonate, 41, 42 

— bromide, 85, 209 

— carbonate, 85, 209 
precipitated, 209 

— chloride, 94, 209 

— fluoride, 86, 192 

— hydrate, 78, 210, 212 

solution, 210, 230 

syrup, 211 

— hydroxide, 78, 210, 212 

— hypochlorite, 211 

— hypophosphite, 195, 212 
granular, 212 

— lactophosphate, syrup of, 213 

— metaphosphate, 99 

— monosulphide, 211 

— nitrate, 94 

— phosphate, 94, 97, 98 
precipitated, 213 

— salts, 207 

impurities in, 209 

sources of, 208 

Calcium sulphate, 94, 208, 211 

— sulphide crude, 211 

— tartrate, 178 
Calcutta nitre, 188 
Cali, 173 

California cinnabar mines, 233 
Calomel, 237, 238, 243 
Calx, 210 

— chlorata, 78, 179, 211 

— sulphurata, 211 
Cane-sugar, 57 
Carbonate of ammonium. 203 



292 



INDEX. 



Carbohydrates, 33, 57, 60, 61 
Carbon, 56 

— active state in, 57 

— compounds of, 56 

— dioxide. 57, 61, 62 

— disulphide, 60, 66 

— monosulphide, 66 

— monoxide, 60, 61 

— occurrence of, 55 

— properties of, 57 

— with halogens, 65 

— with hydrogen, 58 

and oxygen, 60 

nitrogen, 65 

oxygen, 61 

sulphur, 66 

Carbonate of ammonium, 203 

barium, 197 

calcium, 18, 65 

precipitated, 209 

— ferrous, mass "of, 257 
saccharated, 257 

— of iron, 248 

pills, 259 

lead. 65, 231 

ointment, 232 

lithium, 206 

magnesium, 65, 217 

potassium, 179 

sodium, 193 

anhydrous, 193 

crystalline, 193 

. dried, 193 

exsiccated, 193 

zinc, 220 

precipitated, 222 

Carbonates, 56, 64 
Carbonic acid, 62 

how prepared, 63 

properties of, 63 

liquid, 64 

gas, 56 

Carron oil, 211 
Catalysis, 24 
Caustic, 210 

— lunar, 245 

— mild, 246 

— potassa, 183, 194 

antidote to, 183 

solution, 194 

— soda, 194 
solution, 194 



Cavendish, chemist, 28 

Celestine, 214 

Cellulose, 61 

Cerate of subacetate of lead, 230 

Ceratum plumbi subacetatis, 230 

Cerium, 237 

— compounds of, 227 

— oxalate, 227 
Chalk, 65, 208 

— comp. powder of, 258 

— drop, 208 

— impurities in, 209 

— mixture, 209 

— prepared, 208 

— troches, 209 
Chalybeate tonic, 258 
Chamber acid, 128 
Charcoal, 7, 56, 58 

— animal, 58 

purified, 58, 143 

— wood, 58 

Charta potassii nitratis, 189 
Chemical affinity, 3, 8 

— constituents of the air, 53, 
54 

— force, 3 

— nomenclature, 19 

— notation, 15 

— philosophy, 20 

— union, 3 
Chemism, 3 
Chemistry, definition of, 3 

— inorganic, 1 

— organic, 56 
Chili nitre, 79, 82 
Chinese vermilion, 243 
Chlorate of potassium, 187, 197 
troches, 188 

sodium, 197 

Chlorates, 78 
Chlorazotic acid, 144 
Chloride of ammonium, 201 

barium, 216 

calcium, 209 

— ferric, 253 

solution, 254 

tincture, 255 

— of iron, 753 

lime, 78, 79, 212 

— mercuric, 234, 237 
corrosive, 234, 237 

— mercurous, 234, 237 



IN'DEX. 



293 



Chloride, mercuric ammonium, 
236 

— of mercury, corrosive, 237 
mild, 238 

silver, 245 

sodium, 195 

zinc, 223 

zinc solution, 223 

Chlorides, 69, 78 

— test for, 78 
Chlorinated lime, 78, 211 
Chlorination, 69 
Chlorine, 66 

— compounds, 70 

— experiments with, 73 
illustrating affinity for 

bases, 77 

— experiments with, illustrating 
bleaching properties, 75 

— experiments with, illustrating 
diffusion of gases, 74 

— experiments with, illustrating 
disinfecting and deodorizing 
properties, 76 

— experiments with, illustrating 
solvent power of chlorine, 77 

— history of, 67 

— in pharmacy, 78 

— liquid, 69 

— occurrence of, 6Y 

— oxides, 70 

— preparation of, 67 

— properties of, 68 

— test of identity, 78 

— with hydrogen and oxygen, 72 

— water, 143 
Chloronitric acid, 144 
Chrom-alum, 176 
Chromate of potassium, 190 

strontium, 215 

Chromic acid, 158 

— oxide, 158 

properties of, 158 

uses of, 159 

Chromium group of metals, 6 
Cinnabar, 233 

— from California mines, 233 

Spain. 233, 243 

Citrate ammonio-ferric, 268 

— of bismuth, 285 
and ammonium, 286 

— ferric, 267 



Citrate, ferric, solution, 266 
wine, 268 

— of iron, 267 

and ammonium, 268 

potassium, 261 

quinine, soluble, 268 

strychnine, 268 

lithium, 207 

magnesium, effervescent, 

219 

— of magnesium, solution of, 

potassium, 181, 219 

effervescent, 182 

mixture of, 182 

solution of , 181 

Citrine ointment, 244 
Clarifying turbid water, 47 
Clay-alum, 225 

Coal, 56 

— gas, 59 
Cohesion, 1 
Coin gold, 161 
Coin silver, 244, 245 
Coke, 56 

Combustion, 62, 100, 102 
Commercial bicarbonate of so- 
dium, 193 

Compound antimony pills. 239, 
281 

— cathartic pills, 239 

— chalk powder, 208 

— iodine solution, 84 

— iron mixture, 259 

— radical, 65 

— solution of iodine, 84 

— iron mixture, 259 
Compounds of carbon with hy- 
drogen, 58 

— of carbon with hydrogen and 
oxygen, 60 

— of carbon with oxygen, 61. 
cerium, 227 

— ferric, 247 

— ferrous, 247 

Constant combining weight, 16 
Constitutional formulae, 170 
Contaminations in mercuric 

chloride, 237 
Copper, 232 

— acetate, 233 

— and ammonium sulphate, so- 
lution of, 274 



294 



IliTDEX. 



Copper, arsenate, 233 

— carbonate, 233 

— group of metals, 6 

— oxide, 35, 333 

— salts, 333 

impurities in, 333 

reactions of, 78, 233 

— sulphate, 232 

— sulphide, 333 
Copperas, 333 
Corrosive chloride, 337 
of mercury, 337 

— sublimate, 337 
Cotton, borated. 111 
Creta prseparata, 308 

Crude ammonium chloride, 201 

— antimony, 378 

— calcium sulphide, 311 
Cryolite, 193, 193, 234 
Crystals, dodecahedron, 99 

— hexagon, 56 

— monoclinic, 87 

— octahedra, 56, 87 
Cupri sulphas, 232 

Cupric ferrocyanide — red, 333 

— sulphate, 333 
Cyanogen, 51, 65, 163 

— iodide, 83 

Cyanide of mercury, 343 

potassium, 187, 190 

silver, 346 

Cyanides, 56, 65, 163 

— double, 163 



Decomposition of grain, 64 
Definite quantities, 8 
Deliquescence, 38 
Density of metals, 160 
Dentistry, anesthetic in, 50 
Deodorizer, 76 
Depilatory, 311 
Destructive distillation, 51, 58, 

59, 200 
Dewar, physicist and chemist, 49 
Dextrin, 61 

Diachylon ointment, 230 
— plaster, 230 
Diads. 14 

Diamond, 7, 56, 57 
Diatomic, 14 
Didymium, 227 



Diffusion of gases, law of, 29 
Dilute hydrobromic acid, 145 

— hydrochloric acid, 144 

— hydrocyanic acid, 65 

— nitric acid, 139 

— nitrohydrochloric acid, 145 

— nitromuriatic acid, 145 

— phosphoric acid, 155 

— silver nitrate, 246 

— solution lead subacetate, 229 

— sulphuric acid, 131 
Dioxide of barium, 216 

manganese, 167, 269 

Diphospboric acid, 151 

Disease germs, 76 

Disinfectant, 76, 79, 197, 232, 

338 
Dissociation, 19 
Distillation, destructive, 51, 58, 

59, 300 
Disulphide of carbon, 66 
Diuretic, 196 
Donovan's solution, 377 
Double salts, 95, 115, 130 
Dried alum, 325 

— ferrous sulphate, 256 

— sodium carbonate, 193 

E 

Effects of heat upon the molecu- 
lar forces, 32 

Effervescence, 63, 113 

Effervescent magnesium citrate, 
219 

— potassium citrate, 183 
Efliorescence, 38 
Elective affinity, 77 
Elements, 34 

— atomic weights of, 15 

— chemical properties of, 8 

— classification of, 5, 6 

— definition of, 3, 4 

— derivation of names of, 5 

— forms of occurrence of, 7 

— gaseous, 7 

— groups and sub-groups, 5, 6 

— halogen group of, 5 

— liquid, 7, 233 

— metallic, 6 

— molecules of, 17 

— names of, 5, 6 

— uou -metallic, 21 



INDEX. 



295 



Elements, oxygen group of, 5 

— physical properties of, 7 

— quantivalence of, 15 

— symbols of, 5, 6, 15 

— table of symbols, quantiva- 
lence, and atomic weights, 15 

Elixir ammonium valerianate, 

205 
Elutriation, 208 
Empirical formulas, 168 
Emplastrum ammoniaci cum hy- 

drargyro, 237 

— f erri, 264 

— hydrargyri, 236 

— plumbi, 23a 

Empyreumatic matter in ammo- 
nium carbonate, 203 

Epsom salts, 217, 221 

— springs, 216. 217 
Equations, definition of, 18 

— functions of, 19, 234 
Equivalency, 14 
Escharotic, 130, 210, 224, 246 
Ether, acetic, 265 
Ethylene. 59, 60 
Experiments v^ith chlorine, 74 

— illustrating its affinity for 
bases, 77 

— illustrating its affinity for hy- 
drogen, 76 

— illustrating its bleaching 
properties, 75 

— illustrating diffusion of gases, 
74 

— illustrating disinfecting and 
deodorizing properties, 76 

— with hydrogen, 30 
Explosion, 70, 212 
Explosives, 197 
Exsiccated alum, 225 

— ferrous sulphate, 256 

— sodium bicarbonate, 193 
Extract, Goulard's, 229 



Fermentation, 64, 178 

Ferri carbon as saccharatus, 257 

— chloridum, 253 

— citras, 267 

— et ammonii citras, 268 

sulphas, 262 

tiirtras, 266 



Ferri et potassii tartras, 261 

quininge citras, 268 

solubilis, 268 

strychninse citras, 268 

— hypophosphis, 259 

— iodum saccharatum, 251 

— lactas, 253 

— oxidum hydratum, 263 
cum magnesia, 262 

— phosphas solubilis, 267 

— pyrophosphas solubilis, 267 

— sulphas, 256 

exsiccatus, 256 

granulatus, 256 

— valerian as, 262 

Ferric acetate solution, 264 
tincture, 264 

— alum, 262 

— ammonium sulphate, 176, 263 

— arsenate, 263 

— chloride, 253 

impurities in, 254 

solution, 254 

tincture, 255 

— citrate, 267 

solution, 266 

wine, 268 

— ferricyanide, 249 

— ferrocyanide, 249 

— hydrate 249, 263 

— hydroxide, 263 

antidote to arsenic salts, 

263 

— hydroxide with magnesia, 263 

— hypophosphite, 154, 259 

— nitrate, solution of, 265 

— oxide, 248, 263 

— oxyhydrate, 263 

— phosphate, normal, 260, 267 
soluble, 267 

— pyrophosphate, 196, 267 
soluble, 267 

— subsulphate, solution of, 196, 
260 

— sulphate, basic, 260 
solution, 261 

— sulphocyanide, 249 

— tannate, 249 

— valerianate, 262 
Feriicyanide of potassium, 249 
Ferrocyanide of copper, red, 232 

— of potassium, 186, 190, 249 



296 



INDEX. 



Ferrous arsenate, 263 

— bromide, 195 

— carbonate, mass of, 257 

mixture of, 259 

pills, 259 

saccharated, 257 

— compounds, 248 

— hydrate. 263 

— hydroxide, 263 

— hypophosphite, 260 

— iodide, pills of, 258 

saccharated, 251 

syrup of, 252 

— lactate, 253 

— sulphate, 256 

dried, 256 

exsiccated, 256 

granulated, 256 

— sulphide, 249 
Ferrum, 248, 251 

— reductum, 258 
Flame, oxidizing, 109 

— reducing, 110 
Fleitmann's test for arsenic, 274 
Flowers of sulphur, 88 
Fluoride of calcium, 86 

sodium and aluminum, 

224 
Fluorine, 86 
Fluorspar, 86 
Foam, 113 
Forces, atomic, 3, 8 

— of attraction, 2 

— molecular, 1 

— repulsive, 2 
Forms of matter, 1 
Formulas, constitutional, 170 
Formulas, empirical, 168 

— functions of, 19 

— graphic, 20, 169, 176 

— kinds of, 168 

— molecular, 168 

— of molecule of compounds, 
18 

elements, 17 

— rational, 120, 169 

— structural, 170 
Fothergill's hydrobromic acid, 

146 
Fowler's solution, 182 
Fiuit sugar, 61 
Fuming sulphuric acid, 131 



Functions of equations, formu- 
las and symbols, 19, 134 
Fused silver nitrate, 246 

G 

Galena, 227 

Gali, 173 

Gas carbon, 56 

— illuminating, 51, 59, 200 

— laughing, 50, 204 

— liquor, ammoniacal, 200 

— olefiant, 59 
Gases, 2 

— densities of, 74 

— diffusion, law of, 29, 74 

— equal volumes of, 9, 17 

— proportion of, by weight, 9 

volume, 9 

Gauzes, borated. 111 
German silver, 161 

Germs, disease, 76 
Glacial acetic acid, 264 

— phosphoric acid, 151 
Glass, soluble, 198 
Glasswort, 172 
Glauber's salt, 128 
Glycerin, 230 
Glucoses, 60 
Glucosides, 61 

Goebel's- Glover's method for hy- 
drobromic acid, 146 
Gold coin, 161 

— leaf, 77 
Goulard's cerate, 230 

— extract, 229 

Granular ammonium chloride, 
201 

— ammonium nitrate, 204 

— ferrous sulphate, 256 

— zinc, 220 
chloride, 221 

Grain, decomposition of, 64 
Grape-juice, 188 

— sugar, 61 

Graphic formulas, 120, 169, 170 
Graphite , 56 

Greeu iodide of mercury, 240 
Griffith's mixture, 259 
Gypsum, 208 

H 
Hgemostatic, 261 
Hair restorer, 231 



INDEX. 



297 



Halogens, 66 
Haloid salts, 162 
Heat, effect upon molecular 
forces, 32 

— specific, 39 

Heavy carbonate of magnesium, 
218 

— magnesia, 218 
Hexads, 14 
Hexagons, 56 
Honey and borax, 114 
Horn silver, 244 
Hydracids, 116, 122 
Hydrargyri chloridum corro- 

sivum, 234 
mite, 234 

— cyanidum, 242 

— iodidum flavum, 240 

rubrum, 239 

viride, 240 

— oxidum flavum, 241 
rubrum, 241 

— subsulphas flavus, 243 
Hydrargyrum, 233 

— ammoniatum, 239 

— cum creta, 237 
Hydrate of barium, 216 
bismuth, 283 

calcium, 78, 210, 212 

solution, 210, 230 

— ferric, 157, 249, 263 

— ferrous, 263 

— of iron, 157, 249, 263 
with, magnesia, 157, 

263 

lead, 227 

magnesium, 217 

potassium, 183, 190 

solution , 183 

— silicious, of magnesium, 216 

— of sodium, 193 

solution, 194 

zinc, 222 

Hydrated alumina, 225, 226 

— oxide of iron, 263 
Hydrates, 33, 37 
Hydrides, 33 
Hydriodic acid, 148 

properties of, 148 

syrup of, 148 

uses of, 149 

Hydrobromic acid, dilute, 145 



Hydrobromic acid, Fothergill's, 

146 
Goebel's- Glover's method 

for preparation of, 146 

impurities in , 147 

preparation of, 145 

properties of, 145 

Squibb's, 147 

test of identity, 147 

Wade's Buchanan's, 146 

uses of, 147 

Hydrochloric acid, 139 

antidote, 143 

dilute, 144 

impurities in, 143 

preparation of, 140 

properties of, 140 

test for, 140 

type, for salt, 93 

uses of, 143 

Hydrocyanic acid, dilute, 65, 

143, 147 
Hydrocarbons, 33, 57, 58, 61 

— substitution derivatives, 59 

— volatile liquid, 60 
Hydrofluoric acid, 86, 91 
Hydrogen, 28 

— antimonuretted, 273 

— arsenuretted, 273 

— chemical energy of, 31 
properties of, 30 

— compounds, 33 

— etymology of word, 25 

— experiments with, 30 

— history of, 28 

— is it a metal ? 31 

— neutralizing qualities, chemi- 
cally, 31 

— occurrence in nature, 28 

— peroxide of, 47 

— physical properties, 29 

— preparation of, 28 

— phosphoretted, 195, 212 

— sulphide of, 91, 96 

— sources, 28 

— tests and experiments with, 30 

— uses in pharmacy, 32 
Hydrosulphuric acid, 91, 96 
Hydrous alum, 225 
Hydroxide of aluminum, 225, 

226 

— of barium, 216 



298 



IKDEX. 



Hydroxide of bismuth, 283 

calcium, 78, 210, 212 

solution, 210, 230 

— ferric, 159, 249, 263 

— ferrous, 263 

— of iron, 249, 263 

with magnesia, 157, 262 

lead, 227 

magnesium, 217 

potassium, 183, 190 

solution, 184 

sodium, 193 

solution, 194 

zinc, 222 

Hydroxides, 33, 37 
Hypnotics, 207, 210 
Hypo, photographers', 198 
Hypochlorite of calcium, 211 
Hyponitrous acid, 50 
Hypophosphite of calcium, 154, 
195, 212 

— ferric, 154, 259 

— of potassium, 154, 183 

sodium, 154, 195, 197 

Hypophosphites, syrup of, 195, 

213 
Hypophosphorous acid, 151, 154 



Iceland spar, 208 
Illuminating gas, 51 

composition of, 59 

purification of, 60 

Impenetrability, 51 
Imperial green, 278 
Impurities in aluminium salts, 

225 
— in ammonium salts, 201 

bismuth salts, 285 

subcarbonate, 285 

subnitrate, 285 

calcium salts, 209 

copper salts, 233 

ferric chloride, 254 

hydrobromic acid, 147 

hydrochloric acid, 142, 143 

iodine, 82 

lead salts, 228 

lithium salts, 205 

magnesium salts, 217 

mercury salts, 234 

potassium salts, 179 



Impurities in silver salts, 245 

sodium salts, 190 

strontium salts, 213 

zinc salts, 220 

Incompatibility, 185 
Indigo, 69 
Inorganic acids, 115 

handling of, 124 

medical properties of, 125 

— chemistry, 1 
Introduction, 1 

lodate of potassium, 185 

sodium, 195 

lodates, 84 

Iodic acid, 83 

Iodide of ammonium, 205 

arsenic, 276 

and mercury, solution 

of, 277 

cyanogen, 82 

— , ferrous, pills, 258 

saccharated, 257 

syrup, 252 

— of lead, 231 
ointment, 231 

— mercuric, red, 239 

— mercurous, yellow, 240 

— of mercury, green, 240 

red, 239 

yellow, 240 

potassium, 185 

silver, 247 

sodium, 195 

starch, 142 

strontium, 215 

sulphur, 190 

zinc, 221 

Iodides, 83, 163 

— test for, 85 
Iodine, 80 

— chloride of, 82 

— compounds, 83 

— compound solution of, 84 

— impurities in, 82 

— ointment, 84 

— pharmaceutical preparations 
of, 83 

— preparation of, 81 

— properties of, 83 

— purification of, 82 

— sources of, 80 

— test for, 85 



INDEX. 



299 



Iodine, tincture of, 83 
Iodized starch, 84 
lodous acid, 83 
Iron, 248, 251 

— acetate , solution of, 264 
tincture of, 264 

— and aloes, pills, 207 

— alum, 176, 262 

— and ammonium acetate solu- 
tion, 255 

— and ammonium citrate, 268 
tartrate, 266 

— arsenate, 263 

— bitter wine of, 268 

— bromide, 195 

— carbonate, mass of, 257 

mixture of, 259 

pills of, 259 

saccbarated, 257 

— chloride, 253 

impurities in, 254 

solution, 254 

tincture, 255 

— citrate, 267 

solution, 266 

wine, 268 

— compounds of, 248 

analytical reactions of, 249 

— ferricyanide, 249 

— ferrocyanide, 249 

— group of metals, 6 

— hydrate, 249, 263 

— hydroxide, 263 

antidote to arsenic salts, 263 

— hydroxide, with magnesia, 263 

— hypophospbite, 154, 259, 260 

— iodide, pills of, 258 

■ saccbarated, 251 

syrup, 252 

— lactate, 253 

— metallic, 248, 251 

— nitrate, solution, 265 

— oxide, 248, 263 

— oxybydrate, 267 . 

— persulphate, solution, 261 

— pbosphate, normal, 260, 267 
soluble, 267 

— pills, 259 

— plaster, 264 

— and potassium tartrate, 266 

— pyrophosphate, 146, 267 
soluble, 267 



Iron and quinine citrate, soluble, 
268 

— quinine and strychnine phos- 
phate, syrup, 267 

— and strychnine citrate, 268 

— reduced, 251 

— salts, 247 

order of derivation, 249 

properties of, 248 

sources, 247 

— scale salts, 265 

— subsulpbate solution, 196, 260 

— sulphate, 256 

basic, 260 

dried, 256 

exsiccated, 256 

granular, 256 

— sulphides, 249 

— sulphocyanide, 249 

— tannate, 264 

— tersulphate solution, 261 

— troches, 264 

— valerianate, 262 

— wire, 251 

Is hydrogen a metal? 81 



Javelle water, 80 
Juice, grape, 188 

K. 

Kalium, 6 

Kelp, 81 

Kermes' mineral, 281 

Kinds of atoms, 3 

formulas, 168 

L. 

Labarraque's solution, 79, 112 

Laborde, French physiologist, 218 

Lactate of iron, 253 

strontium, 216 

Lac sulphur, 90 

Lactophosphate of calcium 
syrup, 213 

Lampblack, 56, 57 

Lanthanum, 227 

Laughing-gas, 50, 204 

Lavoisier, chemist, 21 

Law of definite chemical propor- 
tion, 8 

— of diffusion of gases, 29 



300 



IlfDEX. 



Law of multiple chemical propor- 
tion, 10, 62 
Lead, 57, 327 

— acetate, 228 
commercial, 229 

— bicarbonate, 227 

— carbonate, 231 
ointment, 232 

— hydrate, 227 

— hydroxide, 227 

— in water, 227 

— iodide, 231 
ointment, 231 

— nitrate, 230 

— oleate, 230 

— oxide, 228 

— oxyacetates, 229 

— plaster, 230 

— properties of metal, 227 

— salts, 227 

antidotes to, 228 

sources, 229 

— subacetate, cerate, 230 

liniment, 230 

solution, 229 

solution, dilute, 229 

— sugar of, 229 

— water, 229, 230 

— white, 231 

Le Blanc's process for sodium 

bicarbonate, 141, 191, 192 
Lepidolite, 206 
Lesson in nomenclature, 71 
Light magnesia, 218 

— magnesium carbonate, 218 
Lime, 210 

— chloride of 78, 213 

— chlorinated, 211 

— liniment, 211 

— slaked, 78, 212 
Limestone, 65, 208 
Lime, sulphurated, 311 

— syrup, 210 

— water, 210, 230 
Liniment, ammonia, 202 

— lime, 211 

— of subacetate of lead, 230 

— volatile, 202 
Linimentum ammoniae, 202 

— calcis, 211 
Liquid elements, 233 

— volatile hydrocarbons, 60 



Liquor acidi arsenosi, 276 

— Ammonii acetatis, 204 

— arseni et hydrargyri iodidi, 
277 

— calcis, 230 

— ferri acetatis, 264 

chloridi, 254 

citratis, 266 

et ammonii acetatis, 255 

subsulphatis, 260 

tersulphatis, 361 

— hydrargyri nitratis, 244 

— iodi compositus, 84 

— magnesii citratis, 318 

— plumbi subacetatis, 229 
dilutus, 229 

— potassae, 184 

— potassii arsenitis, 182 
citratis, 181 

— sodae, 194 
chloratse, 198 

— sodii arsenatis, 198 
silicatis, 198 

— zinci chloridi, 223 
Litharge, 228 
Lithii benzoas, 306 

— bromidum, 306 

— carbonas, 306 

— citras, 307 

— salicylas, 307 
Lithium, 305 

— benzoate, 306 
uses of, 306 

— bromide, 206 

— carbonate, 206 

— citrate, 207 

— properties of, 205 

— salicylate, 207 
Lithium salts, 205 

impurities in, 205 

sources, 206 

tests, 206 

Litmus, 70, 76 

Liver of sulphur, 183 
Lixivia tiou, 81 
Lugol's solution, 84 
Lunar caustic, 245 

M. 

Magnesia, 216 

— alba, 217 

— calcined, 218 



IKDEX. 



301 



Magnesia, heavy, 317 

— light, 217 

— nigra, 217 

— ponderosa, 218 
Magnesii carbonas, 217 

— citras effervescens, 219 

— sulphas, 217 
Magnesium, 216 

— bromide, 85 

— carbonate, 65, 217 

heavy, 218 

light, 218 

— citrate, effervescent, 219 
solution, 218 

— group of metals, 6 

— hydrate, silicious, 216 

— hydroxide, 218 

— silicious hydrate, 216 

— sulphate, 94, 217 
impurities in, 217 

— sulphite, 219 
Magnetic oxide of iron, 248 
Manganese, black oxide, 22, 67, 

217, 269 

— carbonate, 269 

— dioxide, 22, 67, 217, 269 

— sulphate, 269 
Mangani, dioxidum, 269 

— sulphas, 269 
Marble, 65, 208 
Marine plants, 80 
Marsh gas, 59, 60 

Marsh's test for arsenic, 273, 279 
Mass, blue, 276 

— ferrous carbonate, 258 

— mercury, 236 

— vallets, 258 

Massa ferri carbon atis, 258 

— hydrargyri, 236 
Matches, manufacture of, 103 
Matter, ultimate kinds of, 3 
Mercur- ammonium chloride, 242 
Mercurial ointment, 236 

— plaster, 236 

Mercuric ammonium chloride, 
239 

— chloride, corrosive, 237 
in calomel, 239 

— cyanide, 232 

— iodide, red, 239 

— nitrate ointment, 244 
solution, 244 



Mercuric oxalate, 342 

— oxide, red, 241 

ointment, 242 

yellow, 241 

ointment, 241 

— subsulphate, yellow, 243 

— sulphate, basic, 243 

— sulphide, 243 
Mercurous chloride, mild, 338 

— iodide, yellow, 240 

— nitrate, 240 

— sulphate, 238 

Mercury, ammoniated, 239, 342 
ointment, 243 

— biniodide, 239 

— chloride, corrosive, 237 
mild, 238 

— compounds of, 233 

mercuric, 234 

mercurous, 234 

reactions of, 235 

— cyanide, 242 

— iodide, green, 240 

red, 239 

yellow, 240 

— metallic, 233 

— impurities in, 234 

— preparations of, 233 

— properties of, 234 [ing, 236 

— metallic, preparations contain- 

— nitrate, 235 

ointment, 244 

solution, 244 

— oleate, 236, 241 

— oxide, red, 341 

ointment, 343 

yellow, 341 

ointment, 341 

— protiodide, 240 

— salts of, 233, 237 

antidote to, 234 

reduction of, 239 

— sulphate, basic, 243 
yellow, 243 

— sulphide, 233 
red, 243 

— with chalk, 237 
Meta, 152 

Meta-arsenate of potassium, 373 
— arsenates, 373 

arsenic acid, 372 

arsenite of potassium, 272 



302 



INDEX. 



Meta-arsenites, 273 

— -arsenous acid, 272 

phosphate of potassium, 272 

phosphates, 153 

phosphite of potassium, 272 

phosphoric acid, 272 

phosphorous acid, 272 

Metal, hypothetical, 199 
Metalloids, 5, 21, 271 
Metals, 5, 6, 160 

— alkali group, 6 

— alkaline earth group, 6 

— bismuth group, 6 

— chromium group, 6 

— copper group, 6 

— chemical properties of, 160 

— densities of, 160 

— difference from non-metals, 21 

— ductility of, 160 

— iron group, 6 

— magnesium group, 6 

— monad, 94 

— platinum group, 6 

— physical properties of, 160 

— unions with the halogens, 162 

— volatility of, 160 
Methane, 59, 60 
Miasms, 76 

Mild chloride of mercur}'', 238 
Milk sugar, 61 

— of sulphur, 90 
Mindererus' spirit, 204 
Mineral acids, 15 
antidotes to, 125 

— turpeth, 243 
Mispickel, 270 
Mistura cretae, 209 

— ferri composita, 259 

— potassii citratis, 182 

— rhei et sodse, 199 
Mitigated silver nitrate, 246 
Mixture, Basham's 255 

— chalk, 209 

— compound iron, 259 

— Griffith's, 259 

— rhubarb and soda, 199 
Molecular forces, 1, 2 

ejffect of cold and heat 

upon, 32 
Molecules, 2, 17 

— definition of, 2 

— internal structure of, 3 



Molecules, resolution of, 3 
Monad metals, 94 
Monads, 14, 94 
Monatomic, 14 
Mouocalcic phosphate, 98 
Monoclinic crystals, 87 
Monosulphide of calcium, 211 
Mousel's solution, 260 
Multiple chemical proportions, 

law of, 10 
Muriatic acid, 139 
dilute, 144 

N. 
Names, chemical, 71 
Natrium, 6 
Natural forces, 1 

— philosophy, 2 

— reciprocity, 55 
Nessler's reagent, 45, 200 
Neutral mixture, 182 

— salts, 95, 164 

Nitrate of ammonium, 204 
barium, 216 

— ferric, solution, 265 

— of lead, 230 

— mercuric, ointment, 244 
solution, 244 

— of potassium, 189 

paper, 189 

silver, 245 

impurities in, 245 

dilute, 246 

fused, 246 

mitigated, 246 

sodium, 94, 192, 197 

Nitrates and nitrites in w^ll- 

water. 44, 45 

— test for, 51 
Nitre, 138, 189 

— Calcutta, 178, 189 

— Chili. 49 
Nitric acid, 50, 134 

dilute, 189 

impurities in, 138 

preparation of, 134 

properties of, 137 

Nitrites in well-water, 44, 45 
Nitrogen, 48 

— compounds of, 49 

— function in nature, 49 

— history of, 48 



INDEX. 



303 



Nitrogen, liquid, 49 

— occurrence, 48 

— oxides, 50 

— preparation of, 49 

— properties of, 49 
Nitrohydrochloric acid, 144 

dilute, 145 

Nitromuriatic acid, 144 

dilute, 145 

Nitrosylchloride, 144 
Nitrous acid, 50, 134 

— oxide, 50, 204 
Nomenclature, chemical, 19, 71 
Non-metallic elements, 21 
Non-metals, 5, 6, 21 

diii'erence from metals, 21 

halogen group, 5 

oxygen group, 5 

Nordhausen sulphuric acid, 131 
Normal bismuth carbonate, 167 

— ferric nitrate, 265 

phosphate, 267 

sulphate, 167 

tartrate, 266 

— sodium sulphate, 167 
Notation, chemical, 15 

O. 

Octahedra, 56, 87 
Official sulphurs, 88 
Oil, carron, 21 
Ointment, blue, 236 

— citrine, 244 

— diachylon, 230 

— iodine, 84 

— lead carbonate, 232 
iodide, 231 

— mercurial, 236 

— mercuric nitrate, 243 

— mercuric oxide, red, 242 
yellow, 241 

— mercury ammoniated, 243 

— red precipitate, 242 

— sulphur, 91 

— zinc oxide, 222 
Oleate of lead, 230 

mercury, 236, 241 

propenyl, 230 

Oleatum hydrargyri, 241 
Oleic acid, 241 

Order of derivation of iron salts, 
249 



Ores, arsenical iron, 270 
Organic chemistry, 58 

— matter in water, 44 
Orpiment, 270 
Ortho, 152 

Ortho -arsenates, 273 
Ortho-arsenites, 273 

— -boric acid, 111 

— compounds, 272 

phosphoric anhydride, 151 

acid, 149, 151 

Oxalate of cerium, 227 

mercury, 242 

Oxalic acid, 217 
Oxidation, 24, 26, 50, 62, 69 
Oxide of antimony, 281 

arsenic, 270, 275 

copper, 232 

— ferric, 248 

— of iron, 248 

lead, 228 

magnesium, 248 

manganese, black, 22, 67, 

217, 269 

— mercuric, red, 241 
yellow, 241 

— of phosphorus, 100, 153 
silica, 98 

silver, 245, 247 

pills, 247 

zinc, 222 

Oxides, 26, 115 

— acid, 115 

— alkaline, 115 

— basic, 115 

— of chlorine, 70 

nitrogen, 50 

non-metals, 72 

— of phosphorus, 100, 102, 103, 
153. 

— similarity to sulphides, 88 
Oxidizing flame, 110 
Oxyacetate of lead, 229 
Oxyacids, 116 
Oxvchlorides, 162 
Oxysalts, 163, 167 
Oxygen, 21 

— and nitrogen as the atmos- 
phere, 51 

— chemical properties of, 24 

— discovery of, 21 

— etymology, 25 



304 



IKDEX. 



Oxygen, experiments with, 24 

— group of elements, 5 

— history of, 21 

— occurrence in nature, 22 

— acids, 116 

— physical properties of, 23 

— preparation of, 23 

— relation to plant and animal 
kingdom, 23 

— tests, 26 

— uses in pharmacy of, 26 
Oxyhydrogen blowpipe, 30 
Oyster shells, 208 

Ozone, 7, 27, 57 

— test for in atmosphere, 27, 101 



Paints, base for, 231 
Pan acid, 128 
Paracelsus, 28 
Paraf-javal, chemist, 214 
Paraphenolsulphonate of sodi- 
um, 196 
Paris green, 277 
Pentads, 14 
Penatomic atoms, 14 
Per-iodic acid, 83 
Permanganate of potassium, 184 
Peroxide of barium, 216 

hydrogen, 47 

Persalts, 33 

Persulphate of iron solution, 261 

Pewter, 278 

Philosophy, chemical, 20 

— natural, 2 
Phosphate of aluminum, 96 

calcium, 96, 97 

precipitated, 213 

iron, 96, 248, 260 

soluble, 267 

— monocalcic, 98 

— of potassium, 96 
sodium, 94, 153, 196 

— tricalcic, 97, 98 
Phosphates, 96 

— of iron, quinine, and strj-^ch- 
nine syrup, 267 

Phosphide of zinc, 224 
Phosphites, 153 
Phosphorated oil, 105 
Phosphoretted hydrogen, 195, 212 
Phosphoric acid, 93, 102, 107, 149 



Phosphoric acid, anhydrous, 151 

dilute, 155 

glacial, 151 

ortho-, 149,151 

varieties of, 151 

— oxide, 100, 102, 103, 153 
Phosphorous acid, 149, 151 

varieties of, 153 

Phosphorus, 96 

— active state of, 100 

— allotropic forms of, 100 

— amorphous, 100 

— antidote to, 101 

— black, 100 

— crystalline, 100 

— experiments with, 101 

— medical properties of, 106 

— occurrence in nat\ire, 96 

— passive state of, 100 

— pills, 106 

— poisonous properties of, 101 

— preparation of, 97 

— properties of, 99 

— red, 100 

— sources of, 97 

— white, 100 

— uses of, 103 

in medicine and phar- 
macy, 104 

Photographers' " hypo," 198 

Physical properties of elements, 
7 

metals, 166 

Physics, 1, 2 

Pictet, physicist, 49 

Pills, aloes, and iron, 257 

— antimony, compound, 281 

— Bland's, 259 

— cathartic compound, 239 

— ferrous iodide, 258 

— of iron carbonate, 259 
phosphorus, 106 

— Plummer's, 281 

— of silver oxide, 247 
Pilulse ferri carbonatis, 258 
Plant-food, 97 

Plaster, diachylon, 230 

— iron, 64 

— lead, 230, 237 

— mercury, 236 

and ammoniac, 237 

Platinum group of metals, 6 



INDEX. 



305 



Plumbi acetas, 228 

— carbonas, 231 

— iodidiim, 231 

— nitras, 230 

— oxidum, 228 
Plummer's pills, 281 
Polishing rouge, 132 
Potash, caustic, 183 
Potassa, 183 

— by alcohol, 183 

— caustic, 183 
antidote, 183 

— cum calce, 184 

— solution, 184 

— sulphurata, 182 

— sulphurated, 182 

— liquor, 184 

— with lime, 184 
Potassi acetas, 181, 196 

— bicarbonas, 180 

— bichromas, 187 

— bitartras, 178, 188 

— bromidum, 185 

— carbonas, 179, 180 

— chloras, 187 

— citras, 181 

effervescens, 182 

— cyanidum, 187, 190 

— et sodii tartras, 188 

— ferrocyanidum, 186, 190 

— hypophosphis, 183 

— iodidum, 185, 190 

— nitras, 189 

— permanganas, 184 
Potassio-citrate of iron, 265 

— ferric tartrate, 266 
Potassium, 177 

— acetate, 181, 196 

— alum, 225 

— and sodium tartrate, 188 

— anhydrochromate, 168 

— arsenite, solution, 182, 276 

— bicarbonate, 180 

— bichromate, 187 
antidote, 187 

— bitartrate, 178, 188 

— bromide, 185 

— carbonate, 179, 190 

— chlorate, 187 
troches, 188 

— chromate, 190 

— citrate. 181. 219 



Potassium citrate effervescent, 
182 

mixture, 182 

solution, 181 

— chloride, 179 

— cyanide, 187, 190 

— dichromate, 190 

— f errocyan ide, 249 

— ferricyanide, 186, 190, 249 

— hydrate, 190 
solution, 184 

— hydroxide, 190 
solution, 1 84 

— hypophosphite, 154, 183 
syrup of, 183 

impurities in, 179 

— iodide, 185, 190 

— meta-arsenate. 272 
arsenite, 272 

— metaphosphate, 272 

— metaphosphite, 272 

— nitrate, 189 
paper, 189 

— permanganate, 184 

— prussiate, yellow, 186 

— salts, 177 

impurities in, 179 

sources of, 177 

tests for, 178 

— sulphate, 190 

— sulphite, 180 

— sulphocyanide, 190 

— tartrate, 188 
Powder, bleaching, 70, 79 

— chalk compound, 208 

— tooth, 209 

— zinc, 220 
Precious stones, 224 
Precipitate, red, 242 
ointment, 242 

— white, 243 

ointment, 243 

Precipitated calcium carbonate, 

209 

— calcium phosphate, 213 

— sulphur, 88, 89 

— zinc carbonate. 222 
Prefixes, 11, 14, 33, 71, 73 
Prepared chalk, 208 
Preparations containing metallic 

mercury, 236 
Primary products, 125 



306 



INDEX. 



Propenyl oleate, 230 
Proportion, definite chemical, 8 

— multiple, law of, 10 
Protiodide of mercury, 240 
Piusslate of potash, yellow, 186 
Prusslc acid, 65 
Pseudotriad, 176, 224 

Pump, air, 52 

Purified animal charcoal, 143 

— sodium bicarbonate, 193 

— sulphide of antimony, 280 
Putrefaction, 64, 79 
Pyrites, iron, 87, 129 
Pyro, 112 

Pyroboric acid, 112 
Pyroacids, 272 
Pyroarsenic acid, 273 
Pyroarsenous acid, 273 
Pyrolusite, 269 
Pyrophosphate of iron, 196 

soluble, 267 

sodium, 196 

Pyrophosphates, 153 
Pyrophosphites, 153 
Pyrophosphoric acid, 112, 152 
Pyrophosphorous acid, 151 

— oxide, 153 
Pyrosalts, 272 



Quadrads, 14 
Quadrivalent atoms, 14 
Quantivalence, 12 

R. 

Radical, 95, 118, 164 

— acid, 95, 118 

— basylous, 95, 118 
Rational formulas, 120, 169 
Reactions, analytical, of alumi- 
num salts, 224 

ammmonium salts, 200 

antimony salts, 278 

arsenic salts, 273 

barium salts, 216 

bismuth salts, 283 

bromides, 86 

bromine, 86 

carbonates. 63 

chlorides, 78 

copper salts, 232 

ferric salts, 248, 249 



Reactions, analytical, of ferrous 
salts, 248, 249 

hydrochloric acid, 140 

iodides, 85 

iodine, 85 

iron salts, 249 

lead salts, 228 

lithium salts, 206 

magnesium salts, 217 

mercuric salts, 235 

mercurous salts, 235 

metaphosphates, 152 

nitrates, 51 

phosphates, 152 

potassium salts, 178 

pyrophosphates, 152 

silver salts, 245 

sodium salts, 190 

starch, 85, 142 

strontium salts, 214 

sulphates, 257 

tannic acid, 249 

zinc salts, 220 

Reagent, Nessler's, 45, 200 

Realgar, 270 

Red cupric ferrocyanide, 232 

— mercuric iodide, 239 

oxide, 241 

ointment, 241 

— phosphorus, 100 

— precipitate, 241 

ointment, 242 

Reduced iron, 258 
Reducing flame, 110 
Reinsch's test for arsenic, 274 
Regia, 144 

Repulsion, 2 
Resolution, chemical, 18 

— of molecules, 3 
Resublimation, 82 
Rex, 144 

Rhubarb and soda mixture, 199 
Rochelle salt, 95, 166, 188 
Rouge, polishing, 132 
Rule of three, 226 

S. 
Saccharated carbonate of iron, 
257 

— iodide of iron, 251 
Saccharoses, 61 

Sal ammoniac, 201 



INDEX. 



307 



Salicylate of lithium, 207 

sodium, 196 

Sand, 98 

Salt, common, 94, 195 

— Rochelle, 95, 166, 188 
Saltpetre, 189 

Salts, 73, 94, 115 

— acid, 95, 164, 166 

— aluminum, 224 

— ammonium, 199 

— anhydrous, 38 

— antimony, 278 

— arsenic, 270 

— barium, 216 

— basic, 164, 167 

— binary theory, 165 

— bismuth, 283 

— copper, 232 

— deliquescent, 38 

— double, 95, 115, 120, 166 

— efflorescent, 38 

— haloid, 162 

— iron, 247 
scale, 265 

— magnesium, 216 

— mercury, 233, 237 

— metallic, 164 

— neutral, 95, 164 

— normal, 166 

— oxygen, 163 

— potassium, 177 

— silver, 244 

— sodium, 190 

— strontium, 213 

— types, 91 

— writing of, 91 

— zinc, 220 

Scale salts of iron, 265 
Scheele, Carl, 21, 67 
Scheele's green, 275 
Scrubber, 60 
Septads, 14 
Serpentine, 217 

— rocks, 216 
Sheep's wool, 178 

Shells of cretaceous animals, 65 

Shot, 161 

Silicate sodium, 198 

solution, 189 

Silicious hydrate of magnesium, 

216 
Silver. 244 



Silver, analytical reactions of, 
245 

— chloride, 245 

— coin, 244, 245 

— cyanide, 246 

— iodide, 247 

— leaf, 244 

— nitrate, 245 

dilute, 246 

fused, 246 

impurities in, 245 

mitigated, 246 

— occurrence, 244 

— oxide, 245, 247 
pills, 247 

— properties of, 244 

— salts, 244 

antidote to, 246 

Simple elective affinity, 77 

— substances, 3 
Slaked lime, 78, 212 

Soap, action of, upon hard 

waters, 42 
Soda, 194 

— ash, 141 

— caustic, 193 

solution, 194 

stick, 193 

— chlorinated, solution, 198 

— liquor, 194 

— and rhubarb mixture, 199 

— water, 63 
Sodii, acetas, 196 

— arsenas, 194 

— benzoas, 196 

— bicarbonas, 193 

— bisulphis, 194 

— boras, 197 

— bromidum, 194 

— carbonas, 192 
exsiccatus 193 

— chloras, 197 

— chloridum, 195 

— hypophosphis, 195 

— hyposulphis, 197 

— iodidum, 195 

— nitras, 197 

— phosphas, 196 

— pyrophosphas, 153 

— salicylas, 1 96 

— sulphas, 197 

— sulphis, 194 



308 



INDEX. 



Sodii sulphocarbolas 196 
Sodium, 190 

— acetate, 196 

— aluminate, 192 

— and aluminum fluoride, 224 

— anhydrosulphate, 168 

— antimonite, 279 

— arsenate, 194, 198 
solution, 198, 227 

— benzoate, 196 

— biborate, 108 

— bicarbonate, 95, 192, 193 

commercial, 193 

purified, 193 

troches, 198 

— bisulphite, 194 

— borate, 108, 192, 197 

— bromide, 194 

— carbonate, 192 

anhydrous, 193 

crystalline, 193 

dried, 193 

exsiccated, 193 

— chlorate, 192, 197 

— chloride, 94, 195 

— hydrate, 193 
solution, 194 

— hydroxide, 193 
solution, 194 

— hypophosphite, 195 

— hyposulphite, 192, 197 

— iodate, 196 

— iodide, 195 

— metaphosphate, 153 

— nitrate, 94, 192. 197 

— paraphenolsulphonate, 196 

— phosphate, 94, 153, 196 

— phosphite, 153 

— pyrophosphate, 153 

— salicylate, 196 

— salts, 190 

— silicate, 198 

— sulphate, 94, 128, 192 

— sulphite, 194 

— sulphocarbolate, 196 

— thiosulphate, 197 
Soil, 97 

Solid sulphuric acid, 132 
Soluble glass, 198 

— iron and quinine citrate, 268 

— ferric phosphate, 267 

— ferric pyropliosphate, 267 



Solution Ammonium Acetate, 

204 
and iron acetate, 255 

— arsenate sodium, 198 

— arsenic and mercuric iodides, 
277 

— arsenite potassium, 182, 276 

— arsenous acid, 276 

— basic ferric sulphate, 260 

— calcium hydrate 210, 230 

— chlorinated soda, 80, 198 

— Donovan's, 277 

— ferric acetate, 264 

chloride, 254 

citrate, 266 

nitrate, 265 

subsulphate, 260 

sulphate, 261 

— Fowler's, 182, 276 

— iodine compound, 84 

— iron citrate, 266 

— Labarraque's, 79, 212 

— lead subacetate, 229 
dilute, 229 

— lime, 210, 230 

— Lugol's, 84 

— magnesum citrate, 218 

— mercuric nitrate, 243 

— Monsel's, 260 

— potassa, 184 

— potassium arsenite, 182, 276 
citrate, 181 

hydrate, 184 

— soda, 194 

— sodium arsenate, 198, 277 
hydrate, 194 

silicate, 198 

— zinc chloride, 233 
Solvay process, 191, 193 
Soot, 56, 57 

Spain, cinnabar mines in, 233 
Specific heat, 39, 40 
Spirit of ammonia. 202 

aromatic, 202 

Mindererus, 204 

Spodumene, 206 

Spontaneous inflammation, 103 

Squibb 's process for hydrobro- 

mic acid, 147 
Stalagmites, 208 
Standard of atomic "weights, 12 
Starch-test, 142 



INDEX. 



309 



Starch, iodized, 84 

Starches, 61 

Steel as reagent, 78 

Strassfurt mines, 178, 180 

Stronger water of ammonia, 201 

Strontianite, 214 

Strontii bromidum, 215 

— iodidum, 215 

— lactas, 216 
Strontium, 213 

— bromide, 214, 215 

— chromate, 215 

— iodide, 214, 215 

— lactate, 214. 216 

— salts, 213 

properties and tests of, 214 

Structural formulas, 170 
Study of acids and salts, 115 
Styptic, 262 
Subacetate lead cerate, 230 

liniment, 230 

solution, 229 

dilute, 229 

Sublimate, corrosive, 237, 238 
Sublimed sulphur, 88, 89 
Subchloride of mercury, 238 
Subcarbonate of bismuth, 283 
Subuitrate of bismuth, 283 
Substitution derivatives of hy- 
drocarbons, 59 
Subsulphate of iron solution, 
260 

mercury, 243 

Suffixes, 73 

Sugar, beet-root 178 

— block. 58 

— cane, 57, 58 

— fruit, 61 

— grape, 61 

— granulated, 58 

— of lead, 229 
milk, 61 

Sulphate of aluminum, 326 

barium, 87 

calcium, 87 

copper, 232 

— ferric, basic solution, 260 
solution, 261 

ammonium, 262 

— ferrous, 256 

dried, 256 

granulated, 256 



Sulphate of magnesium. 94, 217 

manganese, 269 

mercury, basic, 237 

potassium, 190 

sodium, 94, 128, 192 

zinc, 220 

Sulphide of antimony, 280 

purified, 280 

arsenic, 270 

copper, 87, 232 

hydrogen, 91, 96 

iron, 87, 248 

lead, 87 

mercury, 87 

red, 243 

zinc, 220 

Sulphides, 87, 91, 96 

— similarity to oxides, 88 
Sulphocarbolate of barium, 197 

sodium, 196 

Sulphocyanide of iron, 249 
Sulphur. 87, 96 

— alkaline ointment, 91 

— crude, 87 

— flowers of, 88 

— iodide, 90 

— milk of, 90 

— occurrence of, 87 

— precipitated, 88, 89 

— preparation of, 87 

— properties of, 87 

— sublimatum, 88 

— sublimed, 88, 89 

— washed, 88, 89 

— with hydrogen, 91 
Sulphurated antimony, 281 • 

— lime, 211 

— potassa, 182 
Sulphuric acid, 125 

— aromatic, 131 

— dilute, 131 

— solid, 132 
Sulphurous acid, 133 
Sulphurs, official, 88 
Supporter of combustion, 31 
Symbolizing chemical facts, 16 
Symbols, 15, 16 

— functions of, 16, 19 
Synthesis, 18, 35 

Syrup of calcium lactophos- 

phate, 213 
ferrous iodide, 252 



310 



INDEX. 



Syrup of hydriodic acid, 148 
hypopbosphites, 183, 195, 

213 

lime, 210 

the phosphates of iron, 

quinine and strychnine, 267 



Tannate of antimony, 283 

iron, 249 

Tannic acid reagent, 249 
Tar, 60 

Tar-well, 60 
Tartar emetic, 282 
Tartaric acid. 96, 188 
Tartrate, ammonio-ferric, 266 
.— antimony and potassium, 282 

— iron and ammonium, 266 
potassium, 266 

— potassium, 266 

— potassium and sodium, 188 
Tartrates, 188 

Tests (see Analytical Reaction s). 
Thermometer, 234 
Thiosulpbate of calcium, 198 

sodium, 197 

Tincture ferric acetate, 264 
chloride, 255 

— iodine, 83 
Tooth-powder, 209 
Triatomic, meaning of, 14 
Tricalcic phosphate, 97, 98 
Troches, chalk, 209 

— iron, 264 

— potassium chlorate, 188 

— sodium bicarbonate, 198 
Turpeth mineral, 243 
Type-metal, 278 

U. 

Ungueutum diachylon, 230 

— hydrargyri, 236 

ammoniati, 243 

nitratis, 244 

oxidi flavi, 241 

rubri, 242 

— iodi, 84 

— plumbi carbonas, 232 
iodidi, 231 

— sulphuris, 91 

— ziuci oxidi, 222 



Univalent atoms, 14 
Universe, estimated composition 
of, 22 

V. 
Vacuum, 52 
Valence, 14 
Valerianate of ammonium, 204 

— iron, 262 

— sodium, 262 

— zinc, 221 

Valerianic acid, 204, 223 
Valeric acid, 204, 222 
Vallet's mass, 258 
Vegetable kingdom, 55 
Verdigris, 233 
Vermilion, 234, 243 

— Chinese, 243 
Vertebrates, 208 
Vienna green, 278 
Vinum antimonii, 288 

— ferri am arum, 268 

citratis, 268 

Vitriol, blue, 232 

— green, 256 

— oil of, 125 

— white, 220 
Volatile liniment, 202 

— liquid hydrocarbons. 60 
Volatility of metals, 160 
Volumetric analysis, 198 

W. 

Wade's Buchanan's method for 

hydrobromic acid, 246 
Washed sulphur, 88, 89 

detection of arsenic in, 89 

Water, 34, 72 

— ammonia, 201 
stronger, 201 

— atmospheric, 39, 40 

— chemical properties of, 37 

— clarification of turbid, 47 

— composition of, 34 

— contamination in, 44 

— fresh, 40 

— general properties of, 36 

— hard, 41 

action of, upon soap, 42 

permanent, 41 

temporary, 41 

— impregnated with lead, 227 

— Javelle's, 80 



INDEX. 



311 



Water lead, 229 

— lime, 210 

— occurrence of, 36 

— of crystallization, 38 

— rain, 55 

— relation to animal and vegeta- 
ble kingdom, 36 

— salt, 40 

— soda, 63 

— transformations of, 34 
Waters, aromatic, 213 

— bitter, 192 

— mineral, 43 

acid, 43 

alkaline, 43 

borax, 43 

chalybeate, 43 

ferruginous, 43 

lithia, 43 

saline, 43 

sparkling, 43 

still, 43 

sul phur, 43 

— natural, constituents present in 
all, 36 

— terrestrial, 39, 40 

— well, contaminations in, 44, 45 

detection of, 44, 45 

purification of, 46, 47 

White arsenic, 275 

— lead, 231 

— vitriol, 220 

Wine of antimony, 283 

ferric citrate, 268 

iron, bitter, 268 

Wines, effervescent, 64 
Wood ashes, 177 

— charcoal, 58 



Wool fat, 178, 180 
Writing of salts, 93 

Y. 

Yellow iodide of mercury, 240 

— mercuric oxide, 241 

ointment, 241 

subsulphate, 243 

— prussiate of potash, 186 

Z. 

Zinc acetate, 222 

— bromide, 221 

— carbonate, precipitated, 222 

— chloride, 223 
solution. 223 

— granular, 220 

— hydroxide, 222 

— iodide, 223 

— oxide, 222 
ointment, 222 

— phosphide, 223 

— powdered, 220 

— salts, 220 

analytical reactions of, 220 

impurities in, 221 

— sulphate, 220 

— sulphide, 220 

— valerianate, 221 
Zinci acetas, 222 

— bromidum, 221 

— carbonas precipitatus, 222 

— chloridum, 223 

— iodidum, 223 

— oxidum, 222 

— phosphidum, 223 

— sulphas, 220 

— valerianas, 321 



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